Looking for A/C Fuse & Relay Box

BTW, a member over at the SaturnFans site recommended this forum.
Very impressive on my first readings.

I'm trying to trace down my wife's A/C issue with her 1997 Buick LeSabre Custom Touring car. This is a very rough estimate, as I cannot access my spreadsheet for the moment, but I believe that the car has 68,000 miles on it.

My wife's car's A/C compressor is not coming on when she activates the system. I've found the fuse box under the dash, driver's left side, but cannot find the other fuse box.
I've been told that there are two fuse boxes, in which each has an A/C fuse. I also cannot find the Relay for the compressor, for I feel that that may be where the issue rests.

It goes without saying, your input is greatly appreciated.

You may want to check the pressures of the refrigrant. When it gets low the unit will not come on.
You should find the fuse and the relays under the hood. Look for a black plastic cover. I have a '95 amd '02 so I am not sure about the '97. The '02 has fuse under the hood and fuse and battery is under the back seat.
If you don't locate the trouble you can try this site:
http://www.autoacforum.com/categories.cfm?catid=2
They are very helpful with ac problems but they are gonna ask you about the pressures

I concur with Buckroo, about the refrigerant being low. If you have the ACC system, (Auto climate control) low refrigerant will cause the temperature display, to blink off/on for two minutes after the ignition is turned on, or after the car starts. (Either one) The blinking display is telling you about a fault in the system. Low Freon is a fault that will keep the compressor from engaging. The fuse under the dash powers the controller & display and the fuse under the hood is for the blower motor. If your display and fan are functional, you do not have a blown fuse! The compressor engage function originates at the controller with the selection of the AC function. The controller then sends a signal to a relay to energize the compressor clutch to run the compressor. If your controller has a “low Freon” fault, it will not command the compressor run relay to energize.:sly:

> Hot Z 28 <
If you have the ACC system, (Auto climate control) low refrigerant will cause the temperature display, to blink off/on for two minutes after the ignition is turned on, or after the car is starts. (Either one) The blinking display is telling you about a fault in the system. Low Freon is a fault that will keep the compressor from engaging. Thank you > Hot Z <, for my car does have the ACC system >Auto Climate Control<The fuse under the dash powers the controller & displayThat was the fuse I checked, of course not knowing at the time it powered the controller & display, as the display continues to function correctly. There is also no issue with the cabin's blower motor.
The compressor engage function originates at the controller with the selection of the AC function It is that controller relay which I'm looking for.
If your controller has a “low Freon” fault, it will not command the compressor run relay to energize With that comment, I've noticed no temperature display 'blink'. If my research is correct, this ACC system, has a diagnostic code feature; with that in mind, if a fuse or relay were to fail, is that not an action which would set off a 'blinking light' ??

I should note, I'll take a closer look at the display window, when I get in the car tomorrow morning. But, as far as I remember, no blinking was noticed, however, I'll make a point of directing my attention to that screen tomorrow.

BTW, your paragraph above was sooo appreciated, for it was in such detail, in terms of specific explanations of the various components. I truly appreciated it.

>Buckaroo<Thank you for the A/C site, I'll follow up your suggestion.

Thanks for the Feedback, now the Saga continues.:cool:
The compressor engage function originates at the controller with the selection of the AC function. It is that controller relay which I'm looking for :meant:
When you select the AC function (by pressing the AC button) on the controller.
Note: The ambient temperature must be above 55 deg and the display temperature setting must be lower than the cabin temperature, in order for the controller to command the relay to energize.:grinyes:
If my research is correct, this ACC system, has a diagnostic code feature; with that in mind, if a fuse or relay were to fail, is that not an action which would set off a 'blinking light' ??
Yes, the controller does have a diagnostic feature; however, on the 1994 up Buicks, a scanner is required to retrieve the codes. I do not think a relay or fuse would trigger a code. The code list below will show you the codes for the pre 94 system. OBD11 systems should be close to the the same thing, with some minor changes for improved diagnostics.

10 or 110 - Ambient Temp Sensor circuit open or shorted.
13 or 113 - In-Vehicle Temp Sensor circuit open or shorted.
15 or 115 - LH Solar Sensor circuit open or shorted.
35 or 135 - Data Line failure - HVAC Control Assembly
38 or 138 - Data Line failure - PCM
40 or 140 - Driver Air Mix Motor circuit open or shorted, or not calibrated
48 or 148 - Long Term Freon Loss
52 or 152 - Keep Alive Memory lost; sets with battery disconnected
66 or 166 - Low Freon
A number (1) prefix, indicates a history trouble code.
I should note, I'll take a closer look at the display window, when I get in the car tomorrow morning. But, as far as I remember, no blinking was noticed, however, I'll make a point of directing my attention to that screen tomorrow.
Most people would not notice the blinking display during daylight hours, unless both eyes were focused on the display. Any dealer or well-equipped AC shop would have a scanner and could scan the system for you. Again, I could be wrong; however, I doubt that the compressor relay would be the problem.:headshake

:cya:

I thought with the R134a and odb-ii systems GM got rid of the low freon indication and respective DTCs in the ACC - Auto Climate Control systems?

One reason being is the refrigerant pressure switch is not just a low pressure switch but a high too. I've experienced no ACC DTCs or the climate control display flashing with a low refrigerant charge. However the charge was low and I had to add R134a refrigerant. The PCM module provides a reference signal of around 5 volts to the pressure switch and the switch provides a representative signal back to the PCM module letting the PCM know the charge is correct or at least within the low and high limits. Then the PCM module will send a low to the AC Clutch relay to engage the compressor. The ACC head unit provides AC REQUEST enable to the PCM module.

This is a list of typical trouble codes displayed by ACC units from around 97 and up. This is from a CJ2 unit. Codes are accessed by taking ACC to diagnostics mode by pressing a combination of buttons on the ACC like AUTO and OFF at the same time. It may be different on this year/model LeSabre but the diagnostics mode which ACC units have now is covered in the GM FSM and can be done DIY by the owner.

Position Description
-00 Error codes
-01 (servo position) 103-107 43-162
-02 (servo position) 128 120-202
-03 (servo position) 150 162-194
-04 CJ2 Fan Speed Low=15, 29, 44, 58, 71, 86, 110=High, CJ2 Unit will adjust to other increments as needed
-05 (servo position) 93 88-191
-06 (servo position) -152 00-252
-07 (servo position) 00 0, 34-255
-08 (servo position) -155 00-255
-09 (servo position) 00 0, 23-255
-10 ? 04 04
-11 CJ2 Vent Mode 1=Def, 2=Bilevel, 3=Auto, 4=Lower, 5=Def+Lower
-12 Engine Coolant Temp -60 degrees 80=104, 95=131, 100=140 Peak@135°F
-13 Actual Vehicle Speed in MPH
-14 (servo position) 00 21=0
-15 ? 39 44
-16 Radiator low fan turn on temp -106 207
-17 Radiator low fan turn off temp 196 199
-18 ? 50 51
-19 (servo position) 162-169 40-172
-20 Affected by cabin temp sensor 89 50-172
-21 (servo position) 00 ?
-22 Sunload Sensor -117 LIGHT=126, 218=DARK

A two digit code indicates a current fault while a three digit code indicates a historic fault.

Trouble Code Description
00 No System Fault
01 or 101 Inside Air Temperature Sensor Short
02 or 102 Inside Air Temperature Sensor Open
03 or 103 Ambient Outside Temperature Sensor Short
04 or 104 Ambient Outside Temerature Sensor Open
05 or 105 LH Electric Actuator Open or Short
06 or 106 RH Electric Actuator Open or Short
07 or 107 UART Serial Data Line Fault
08 or 108 Solar Sensor Open

I thought with the R134a and odb-ii systems GM got rid of the low freon indication and respective DTCs in the ACC - Auto Climate Control systems?
Bob, thanks for the additional “more up-to-date” info. I do not have a FSM on the 97 and that is the reason I made reference to the pre 94 systems and how they work. You may be right about the low Freon (pressure) not setting a DTC.
Codes are accessed by taking ACC to diagnostics mode by pressing a combination of buttons on the ACC like AUTO and OFF at the same time. It may be different on this year/model LeSabre but the diagnostics mode which ACC units have now is covered in the GM FSM and can be done DIY by the owner.
This may be :screwy:; however, I have never seen nor heard, of anyone being able to access the diagnostic mode in 94 up systems, without the use of a scanner. If you can find the information giving details on how to do it without a scanner, please post that procedure. That would be some great new information to have and would be worthy of a “sticky” thread.
Thanks again for your support!:cya:

> Fm Hot Z <
> What I meant to say = Pressing the AC function button on the controller <As in 'controller' panel, center dash panel ??

I understand the temperature must be 55+, with the display temperature setting being lower than the cabin temperature. But something tells me that when you refer to the "controller", you do not mean the display setting, but mean an actual component, called a "controller". ??

As to the diagnostic feature of the system, and fully understand that one needs a On-Board Diagnostic 2 (OBD-11) reader/scanner, but, I return to the "blinking display" light, at the time of initial ignition start up. I'll be checking that in about an hour.

>Most people would not notice the blinking display during daylight hours, unless both eyes were focused on the display<As the car is garaged, it will be easy, as well as I'll be directing my attention solely to the display--after turning the key to the on position, and then to the start position.

> Fm B Naylor <
> I thought with the R134a and odb-ii systems GM got rid of the low freon indication and respective DTCs in the ACC - Auto Climate Control systems? < That may be the case, for a couple of months ago, when it was noticed that the exiting air was not that cool, no ACC display flashing was noticed (( That may simply, though, have been because, I had not been alerted to check that out. ))

>Codes are accessed by taking ACC to diagnostics mode by pressing a combination of buttons on the ACC like AUTO and OFF at the same time.<I'll try that, as I assume, such an effort would notneed a OBD-II reader/insert.

I'm also assuming, that should a ACC DTC (( Auto Climate Control system Diagnostic Trouble Code )) be 'set', that an initial alert would be the flashing dash panel, upon initial engine startup.

> Fm Hot Z <
> I have never seen nor heard, of anyone being able to access the diagnostic mode in 94 up systems, without the use of a scanner < I'll, atleast, check that out when I start the car. If the display does flash, that may be the extent. It will only tell me, that a code(s) has/have been set. But I will report back tomorrow.

>That would be some great new information to have and would be worthy of a “sticky” thread.
<Actually, most of the information so far submitted on this thread could well go into a "sticky".

This truly has been very informative.
I'll report back.

Thank you, Luke

Well, yesterday, when I started the car, there was no flashing on the ACC display; The 'outside' temperatue remained constant. I should also note, that there also was no reaction when I pressed the Auto and Off buttons, simultaneiously. Display continued to present the outside temperature >57 degrees <

A friend has an OBD-II scanner, so I'll be borrowing it. I'm assuming that the it is to be inserted into a DLC >Data Link Connector< under the dash, driver's side. >Atleast that is where the DLC is located on my Saturn. <
> Hot Z <I could be wrong; however, I doubt that the compressor relay would be the problemAs I sense that relays rarely fail, it is for that reason I'm initially looking for the 2nd fuse, as I've read that there are two with this ACC >Auto Climate Control< system.

I borrowed a "Innova #3100 Digital OBDII code reader" (((>and of course, it's owner's manual <))) and will be using it this weekend. In addition to 'generic' codes covering A/C refrigerant pressure issues & A/C Clutch relay control circuit -high/low- issues, it also covers General Motors specific codes.

With all that said, one would think, that the failure of the compressor engaging, a code would have been set.

Oh well, will report back.

I borrowed a "Innova #3100 Digital OBDII code reader"

A good link (http://www.troublecodes.net/articles/equus/Equuis_OBD_II_code_reader.shtml) on the "Innaova 3100" FYI.:smile:

I borrowed a "Innova #3100 Digital OBDII code reader" (((>and of course, it's owner's manual <))) and will be using it this weekend. In addition to 'generic' codes covering A/C refrigerant pressure issues & A/C Clutch relay control circuit -high/low- issues, it also covers General Motors specific codes.

With all that said, one would think, that the failure of the compressor engaging, a code would have been set.

Oh well, will report back.

I did look up the relay location for the compressor and it's the one at the far left of the Relay Center (passenger side). The service manual (1998) says to check with a fused wire to see if the compressor clutch will engage with a fused direct link to the battery -- first.

The relays in the center are often the same number so they can be interchanged. You might try that after the clutch check on the compressor.

I'll look for the fuses again (I forgot what I found) and post.

I find fuse Auto A/C Cruise Fuse 5A
Fuse 9C for MSC/RDO/CLSTR looks like keep alive it's hot all the time.
The number is the column and the letter is the row if I recall correctly
And I find a fuse 7E 10A called Non OBD II MISC ENG and it powers the clutch relay!!!!

I assume all three of these are in the fuse block by driver's left knee. There is another fuse block above the passenger foot inside the hush panel is a picture showing which fuses and relays are there. The panel is on the A pillar area under the dash to the right of the glovebox.

I just checked my hush panel since it's off and in the trunk-there's a fuse For Non OBD II MISC Eng on that panel against the right side. It looks like there are two or more vertical columns of fuses on my 1998 and the top one second from the front of car is the Non OBD II MISC ENG.
Note all three of these fuse are listed as IP Fuse block. I guess they just don't say which fuse block in the service manual. And the fuse is not 7E in the main IP panel next tot he driver!

That may be the fuse you're looking for!!! It powers the relay pull in circuit when grounded by the PCM and it supplies thepower for the relay to connect to the clutch to ground and engage the clutch.

Good luck.

(Just checked owners manual in car and it shows a 7E under the driver's side as Non OBD II Engine controls. I didn't check the actual panel since the car's in the garage and I like to crawl upside down under the dash with it outdoors to have room.

>Hot Z< Wow, super site, thank you....
Fm imidazol97
the relay location for the compressor and it's the one at the far left of the Relay Center (passenger side) I'll take a closer look in that area, for initially, I did not notice a Relay Center (passenger side).
The relays in the center are often the same number so they can be interchanged. You might try that after the clutch check on the compressor. Understood, and shall do. I'll use the 'horn' relay, if it is the same stock number.
And I find a fuse 7E 10A called Non OBD II MISC ENG and it powers the clutch relay!!!! Man that is a Very Good find, I believe that that fuse is in the box, located on the left of the driver's side, left knee area: I had thought that the clutch fuse was going to be located in the fuse box, which I thought was over on the passenger's side 'hush' panel. I believe that your right about the three, of them are located there. (((>Fuses 5A, 7E, 9C<))) I'll Follow-up and of course report back. ...
I just checked my hush panel since it's off and in the trunk-there's a fuse For Non OBD II MISC Eng on that panel against the right side. It was that very location I initially checked, but sensed I'd have to lift up the carpeting on the passenger's side. Is that box higher up, on the foot rest area, passenger side ??? For it was that fuse, which I felt was the one which would power the relay, since I sensed that the #7E, being a 10 amp unit, was not high enough for a A/C compressor.
That may be the fuse you're looking for!!! It powers the relay pull in circuit when grounded by the PCM and it supplies the power for the relay to connect to the clutch to ground and engage the clutch. In my reading of the actual wiring circuitry, I've come up with the same findings, however, you've clarified doubtful information I had.


I'll also be checking fuse # 7E.

Thank you....

Fm imidazol97
I find fuse Auto A/C Cruise Fuse 5A
Fuse 9C for MSC/RDO/CLSTR looks like keep alive it's hot all the time.
The number is the column and the letter is the row if I recall correctly
And I find a fuse 7E 10A called Non OBD II MISC ENG and it powers the clutch relay!!!! I went through my wiring diagram, and found the three fuses; However, the 7E was rated as a 20Amp fuse. The #9C is rated 10 amps, while the #5A is rated 15 amps.

Atleast this give me information when I check the actual fuse box.

And the fuse is not 7E in the main IP panel next tot he driver! Do I understand you to be saying that the #7E is not the same one as the 7E in the fuse panel in the upper driver side panel ??

I Do I understand you to be saying that the #7E is not the same one as the 7E in the fuse panel in the upper driver side panel ??

Right. My glovebox manual show the NonOBDII fuse in the driver's side panel. I didn't check. But the same label is on a fuse over at the right side fuse/breaker/relay panel and it should be 10 amp. Maybe there's a duplicate in the circuit--I haven't crawled into mine since it's hard to see the driver's side panel and I like to be outdoors so I can open the car doors.

It was that very location I initially checked, but sensed I'd have to lift up the carpeting on the passenger's side. Is that box higher up, on the foot rest area, passenger side ??? For it was that fuse, which I felt was the one which would power the relay, since I sensed that the #7E, being a 10 amp unit, was not high enough for a A/C compressor.
In my reading of the actual wiring circuitry, I've come up with the same findings, however, you've clarified doubtful information I had.


I'll also be checking fuse # 7E.

Thank you....

The panel on passenger side requires removing the thin plastic panel under the dash that quiets noise from engine. The panel is up high about 10 inches above the floor on passenger side.

>imidazol 97< Thank you, though, I'm hoping that I don't have to go their.

I'll be checking tomorrow afternoon. And, of course, will be reporting back. :smile:

With a GM Tech II scan tool you can command the comp clutch thru the PCM module but there are manual troubleshootng procedures to use in lieu of to check to see if the A/C Clutch Relay is energizing. Once you find out where the A/C Relay is located you can do the following diagnostics. In most late model Buicks the A/C Clutch Relay is typically located in the underhood fuse compartment.

Does the clutch come on if you jump terminal 30 and 87 of the relay?

Does pin 86 show continuity to ground when the A/C is requested.

The HVAC module sends a signal to the PCM across the Class 2 data line to let the PCM module know the A/C has been requested.

The PCM looks at the A/C pressure sensor reading and then grounds terminal 86 to energize the coil on the relay. If this happens, 12v should be pressent at the compressor.

Here is some info on the pressure sensor:
The A/C pressure sensor is mounted on the discharge line of the A/C compressor hose assembly. The sensor's output to the powertrain control module is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output.

A/C pressure is constantly monitored in order to allow the A/C clutch to disengage due to aberrant pressures:

If the pressures are above 2968 kPa (430 psi)
If the pressures are below 255 kPa (35 psi)

Here is how the A/C system operates:
The engine belt-drives the compressor for the air conditioning system through the A/C compressor clutch. The clutch allows the compressor to cycle on and off. During most normal operation, the compressor will be in the ON position. The compressor will disengage under the following conditions:

When the air conditioning is OFF
When the engine load must be reduced
When the automatic system requests the system FRONT DEFROST or A/C, the heater and A/C programmer sends a request message for the compressor. The request message travels over class 2 serial data communications to the Powertrain Control Module (PCM).

Under normal operating conditions, the PCM supplies a ground to the A/C compressor control relay coil, and the relay energizes. The A/C CLU fuse and the A/C compressor control relay contacts supply voltage to the A/C compressor clutch. The A/C compressor clutch engages, and the compressor runs.

If the PCM determines that the engine load needs reducing, such as during full throttle conditions, the PCM will de-energize the A/C compressor control relay. De-energizing the relay will disengage the compressor, even though the voltage signal from the heater and A/C programmer is still present.

The A/C compressor clutch diode is connected across the A/C compressor clutch terminals. The A/C compressor clutch diode provides a path for the current that results from the voltage spikes. The collapsing magnetic field of the A/C compressor clutch coil generates the voltage spikes. Voltage spikes occur every time the coil energizes.

> B Naylor < As my wife has the car this morning, there will be a delay in my follow-up.

Initial observations: (( And of course, we have to go to a dinner this afternoon )) Upon rechecking, for the third time, but this time, the full fuse panel/box, under the driver's side dash, I find a fuse slot 5D > 25 A, Base A/C. It's missing, as in empty. Hmmmmmmmm. So I took a 25Amp unit from the #2D Spare slot.

As the weather this Christmas day in Los Angeles is warm, I'll see if this "empty" slot has anything to do with the A/C being inopertive. BTW, this is not a situation where this slot is supposed to be vacant. It's supposed to be fused.

This may be a remote find, with no influence on the A/C compressor activation, but it's an observation.

I should note, additionally, in checking the back center of the engine compartment, after cleaning a light dust layer on the back, low and behold, I find a VERY large covering for the Maxifuse/Relay Center.
Ok, I'm not embarrassed. :headshake , So I'm not the brightest living cell getting off the turnip truck..:shakehead

I'll report back in the morning, with the results of the trip to dinner.

Merry Christmas, you all......:grinyes:

Well, I've taken time out from dinner -- there was no change to the A/C system. It did not work.

Will report back later.

BTW, in using the Diagnostic Scanner, there were no codes....

The next time I test it, I'll try the A/C "Auto & On" button, at the same time; I want to take those steps to see if the system goes into a Diagnostic test.

Until next time.

In checking the 'Maxifuse / Relay Center' (((> located under hood, and back firewall area, center & left of center cover. <))) the 30 amp fuse was found to be good.

As my wife had to use the car, it will be next weekend, before I'm able to check the car's cabin passenger side's fuse box. The observation of the A/C's clutch engaging requirement, will be checked when my wife come's home, with the car's engine still running.

It should be noted, the only notation on the dealer's work order was
" Air conditioner replacement recommened and declined."

That was it. No notation of effort, or results, from the actual technician. Remarkable.

Reporting, to continue.....

I've been working from a copy, made available from this site, of a Acrobat Reader for the 1998 Buick LeSabre Limited.

I'm sensing that the wiring may be different, with particular emphasize on the respective fuse boxes, and fuses on my 1997 Buick LeSabre Custom :frown: from the 2004 Mitchell Repair Information company's manual titled: 1997 Buick LeSabre Limited A/C-HEATER SYSTEM - AUTOMATIC , which I found here.

May I ask if anyone can direct me to a similar manual, for my
1997 Buick LeSabre Custom ???

Most appreciative

1997 Buick LeSabre Limited w/grand touring suspension package.


Ok Guys, here is what I check this afternoon (Sunday)

Attempted, but was not successful in, checking the 'relay switch', which is supposed to be in the "MaxiFuse/Relay" section in the back of the engine compartment [ center, center left ] My problem was that the was no sticker on the master cover panel, which should have indicated which of the four relay switches was for the A/C. Of course, as I understand, all four are the same, however, I did not want to switch any of them, for fear of shutting down something critical.

I was able to get under the passenger side's upper leg panelling, to check the fuses there, and the one for the "A/C Programmer" was found and pulled & checked. It was fine. (( I should note, it was not that difficult to access that fuse panel. It just required removing two small supporting 'screws' holding the knee panelling up, while then slipping the back firewall bolt securing supports, and the knee panel just dropped down. ))

Moving along to my running the engine: Ran at operating temperature, with outside temperature being 70 +/-. Here's what I noticed; Upon pushing the "automatice" button, the interior fan came on to it's initial high speed. Outside temperature registered as 73 on the center panel, with my setting the A/C temperature reading to 65.

Interestingly, not only did the compressor not activate [come on, as in the compressor's clutch engaging], but neither of the two fans on the radiator were activated. I noticed no difference in the RPMs, nor here the Relay Switch's magnetic "click".

I also took the steps to turn the HVAC to windshield, thinking that the A/C is also supposed to engage when that request is made. Results, also, the same.....no engagement of the compressor, nor radiator fans coming on.

With these results, my next inquiry will be that of the freon level (or what ever is used in the newer cars---R122 ????). If memory serves me correctly, these, and probably all cars, have a shut off switch, whereby, should the freon exceed, or drop below a given threshold figure, the A/C computer will have received that reading, and not allow the A/C to engage -- thus saving the compressor from damage, due to low, or excessively high freon pressure readings.

Of course, if that is the case, then a "leak" will have to be found.

Reports to follow, with appreciation for any input from you all.

With these results, my next inquiry will be that of the freon level (or what ever is used in the newer cars---R122 ????). If memory serves me correctly, these, and probably all cars, have a shut off switch, whereby, should the freon exceed, or drop below a given threshold figure, the A/C computer will have received that reading, and not allow the A/C to engage -- thus saving the compressor from damage, due to low, or excessively high freon pressure readings.

Of course, if that is the case, then a "leak" will have to be found.

Reports to follow, with appreciation for any input from you all. You may want to check the pressures of the refrigrant. When it gets low the unit will not come on.
I concur with Buckroo, about the refrigerant being low.
Here is some info on the pressure sensor:
The A/C pressure sensor is mounted on the discharge line of the A/C compressor hose assembly. The sensor's output to the powertrain control module is variable and is dependent upon pressure inside the line. A higher pressure results in a higher voltage output.

A/C pressure is constantly monitored in order to allow the A/C clutch to disengage due to aberrant pressures:

If the pressures are above 2968 kPa (430 psi)
If the pressures are below 255 kPa (35 psi)
I would agree, get the Freon level checked!:sunglasse

Can that Sensor's Output be checked ???? I do have a volt/amp tester.


As a side, info, note; It should be stressed that, upon initial reading about obtaining access to the fuse box on the passenger's side, it was actually rather simple. The paneling which had to be removed, was the panel which sits just above the passenger's knees, and sits just below the glove box door. The actual fuse box, sits on the side wall, to the right of the passenger's right knee. One can actually 'see' the box, when the glove box is opened beyond the rubber stop points.

Before you get into that did you consider HotZ28's suggestion about checking the refrigerant charge? You have a low pressure port most likely at the firewall where it can be checked with standard A/C gauges with adapters for R134a systems. Also, there is a high pressure port by the accumulator. The low port is easier to check DIY.

The pressure sensor is both a lo/hi type. The output is not that easy to check since it is supposed to vary based on the refrigerant charge and the electrical connector must be left on. The PCM module provides approximately a 5 volt reference signal to the sensor then the sensor outputs a DC voltage representative of the system pressure. Unlike older A/C systems the sensor cannot be jumped or bypassed. A resistor simulating normal pressure between the low and high threshold voltages must be used.

If charge is good the next easiest step is to bypass the A/C Clutch relay at the normally open or closed contacts to see if the compressor engages.

Fm B Naylor
..did you consider HotZ28's suggestion about checking the refrigerant charge? I'm considering that now, however, the two guage set-up I have, I've only used on the old A/C systems, with my never having to do it on a R134a system. I'll look for the 'low port' connection.

If charge is good the next easiest step is to bypass the A/C Clutch relay at the normally open or closed contacts to see if the compressor engages. My problem with that, is that of the two relays, sitting under the panel of fuses, neither is labeled. Reminder: there are two separate fuse rail/bus, with two relay switches under each fuse rail/bus. I'm assuming that one of the two, sitting below the rail which houses the 30a A/C fuse, is sitting there.

The output is not that easy to check, since it is supposed to vary based on the refrigerant charge.
and the electrical connector must be left on

Thank you for that specific information. Very informative, and of course, helpful.