'91 Park Ave. - climate control question

Hi there,

on my '91 Park Avenue the climate control suddenly can not be switched
to "Auto" anymore but stays on or goes to "Econ" instead if I press the
"Auto" button - meaning that I cannot cool the car anymore.

All other functions of the dashboard control unit seem to work.

Does this mean that probably the dashboard control unit is defective?

Does anybody know how to replace this control unit? It seems to be fixed
with 3 screws (2 at the sides, 1 at the top) – but how to remove the long black dashboard panel?

I would be very grateful if some of you could give me some hints.

Thanks a lot

PS: I've added a picture of the control unit.

there is an auto button on the top left. Be sure to press the auto button on the fan speed control too, or you'll still be in economy. It is the second row, 4th button over.

there is an auto button on the top left. Be sure to press the auto button on the fan speed control too, or you'll still be in economy. It is the second row, 4th button over.

... thanks. I tried that, too. Doesn't help. In the first row the light switches always and only to the "Econ" button if I push the "Auto" button (in the first row). So - all my questions are still there.

The econ mode is the default setting when you have a problem. I would bet you that you have lost your AC charge and the car will have a code stored for low freon!! I would even bet you that your evap core on your car is leaking causing your problem. The repair for this is about 500 dollars.

If you remove your blower motor resistor look inside at the evap core if you see black stuff stuck to the cooling fins than your evap core is leaking. I replace at least 20 evap cores a summer in the older cars like yours.

just so you know your car has no relays for the blower motor...everything is controled by the HVAC programmer and the blower control module...the programmer is located under the passengers side dash u have to take apart most of the dash for this..the best thing to do is buy a haynes manual...it tells u there how to do it...the blower module is located under the hood under the large fuses and relays three screws takes it out...i would goto a junk yard and pick one up they are cheap (10$) if that doesnt work...take ur car to a autozone then can check ur car for anycodes for free...even if ur service engine soon light isnt on there still might be codes...thank you and have a nice day

Hi there,

on my '91 Park Avenue the climate control suddenly can not be switched
to "Auto" anymore but stays on or goes to "Econ" instead if I press the
"Auto" button - meaning that I cannot cool the car anymore.

All other functions of the dashboard control unit seem to work.

Does this mean that probably the dashboard control unit is defective?

Does anybody know how to replace this control unit? It seems to be fixed
with 3 screws (2 at the sides, 1 at the top) – but how to remove the long black dashboard panel?

I would be very grateful if some of you could give me some hints.

Thanks a lot

PS: I've added a picture of the control unit.Had the same problem with my 91 Park Avenue Ultra. About 1 lb. freon and it was up and running. Milt.

Had the same problem with my 91 Park Avenue Ultra. About 1 lb. freon and it was up and running. Milt.

I had the same problem with my 91 Park Avenue, the level of freon was too low,so it would only run on "economy" but I had to convert the Air conditioner to a another sort of freon before they would fill it up, the old freon was not allowed to use here in Sweden anymore.

They changed some parts of the AC and filled it up whith new freon.
The price for this job was about 300 in US $.
-Works perfectly now!

Sandvik
Sweden

I have similar problem with my 91 P/A No trouble codes. A/C compressor would engage in auto, then revert to econ. The clutch separted on the compressor so I replaced compressor, flushed components, new orifice, and recharged with R134a. Original problem still present. I can clear codes and press HI then compressor engages and operates for about 1 minute or less then kicks out. It will remain in ECON until I reset during self diagnostics. Low side drops to 25-35 and High side 170 to 230 any insight would be great. This has been expensive enough so far and I don't want to just shot gun unnecessary parts.

I have the exact same problem as ldelka on my -91 P/A.

No trouble codes, just had the system recharged, and still it won't enable the compressor unless I check the error codes (which always state "00"). After that the air conditioning goes to Auto and compressor kicks in, but in 1-2 minutes it slips back to Econ and after couple minutes more turns off the compressor with a hissing sound.

So the compressor itself should be ok since it runs, perhaps there is a faulty freon level sensor or something?

1991 Park Ave with 195,000 Km in mint shape. A\C was stuck in the ECON mode, basically no A\C, and would not go into AUTO. Had R134 recharged with 2 valves replaced ($220cd) due to a some leaks, but still had the same problem. Steve, on this forum, had the same problem and said to disconnect the battery, turn the key on and it should reset the error log. I did that and WOW, it worked. Climate control A\C now works great. Saved me a thousand bucks at the dealer. Many thanks.

I have the exact same problem as ldelka on my -91 P/A.

No trouble codes, just had the system recharged, and still it won't enable the compressor unless I check the error codes (which always state "00"). After that the air conditioning goes to Auto and compressor kicks in, but in 1-2 minutes it slips back to Econ and after couple minutes more turns off the compressor with a hissing sound.

So the compressor itself should be ok since it runs, perhaps there is a faulty freon level sensor or something?

----------------------------------------------------------------------
Even though I had my negative cable disconnected when I performed the R134a retrofit, I encountered this problem after/during servicing. I disconnected the negative cable and walked away. I came back about an hour later, reconnected the negative cable and the problem went away. The only problem I have had since then with this system is the bolwer motor failed to come on a couple of times, but it didn't fail long enough to isolate yet.

Ok, I tried disconnecting the negative battery cable one morning before a longer ride, and the problem seemed to go away. System stayed on Auto and cooled the air just fine, but after about one hour of driving it slipped back to Econ and I'm back in square one.

Strange thou that now the system had an error code, "152" if I remember correctly. I think I read from somewhere that it's a history code (1xx) for low freon (52), but please correct me if I'm wrong.

Also the AC would still turn on whenever I checked the error codes by pushing "off" and "warm" at the same time, seems like the error code checking mode also serves as a diagnosis mode that tests all systems?

Ok, I tried disconnecting the negative battery cable one morning before a longer ride, and the problem seemed to go away. System stayed on Auto and cooled the air just fine, but after about one hour of driving it slipped back to Econ and I'm back in square one.

Strange thou that now the system had an error code, "152" if I remember correctly. I think I read from somewhere that it's a history code (1xx) for low freon (52), but please correct me if I'm wrong.

Also the AC would still turn on whenever I checked the error codes by pushing "off" and "warm" at the same time, seems like the error code checking mode also serves as a diagnosis mode that tests all systems?
Code 152 is Keep Alive Memory lost; sets with the battery disconnected

Code 66 or 166 is low freon

found this site while looking for info on my OLDS ... identical problems but found in on a pontiac site

http://www.bonnevilleclub.com/techinfo/?article=45

I have a 91 Park Ave, A/C just recharged to spec with 134A.
Pressure Cycling, High Pressure and Super Heat switches all check out.
Still goes to Econ after 1 to 5 minutes after reset.
Code 138 - history of Serial Data Error From PCM is logged.
I replaced the control head and Ohmed all connections between PCS, Controller and Programmer. Same problem Exists.
I read this thread and disconnected my battery.
Problem Solved :wink:
Thanks to all who contributed here, lesson learned, Don't over-look the obvious.
If anyone needs them here are the codes:
Climate Control Diagnostics
This procedure will work on 1992 and 1994 models with ATC, and may possibly also work on 1988-1991 models.

The diagnostic mode also contains a data list mode and an override mode.

Be careful not to select modes 01 or 02, as these are different modes, and may cause problems.

If you suspect you are in the wrong mode, press OFF repeatedly until you exit to normal mode. If the temperature display flashes for 2 minutes when the ignition is turned to RUN, a code is set.

1. Turn ignition to RUN. Press OFF and WARM (temperature up) buttons simultaneously.

2. Watch the segment test, then the trouble codes will be displayed.

3. Code Key:

00 - No codes

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
Press OFF twice once codes are displayed to end diagnostic mode, OR to clear trouble codes, press FAN DOWN three times
(make sure 03 is isplayed).

Once 03 is displayed, press FAN UP to clear trouble codes. Then repeatedly press OFF to end diagnostic mode.