Cooling Issue...Please help

[teafreak35]

I've noticed lately that my air conditioner in my 1999 malibu isn't cooling as well as it was just a month or so ago. Today, the air temp outside is 97 degrees. My engine temp is running right around 200 degrees. Normally it runs around 180. The air conditioner puts out minimally cool air, NOT COLD. It cools better at highway speeds than while driving around town. It seems that the higher the engine temp goes, the less the ac cools. I checked the refrigerant level in the ac last week and it was right at 52 psi according to my gauge...I think 55 is the high limit.

Here's what has me confused. No matter how hot the car gets or how high the ac is turned up, only one coolant fun runs. When I first crank the car, the fan on the passenger side of the radiator will come on briefly, but turns slowly, then turns off to never come back on again. Driver's side fan runs from the time you crank the car until after the car is shut off.

Should both of these fans be running under the conditions that I described above? And...if one of these isn't working, could that cause my ac not to cool as well as it should? I'm confused at this point...any help is appreciated!!

[inafogg]

Originally Posted by teafreak35

I've noticed lately that my air conditioner in my 1999 malibu isn't cooling as well as it was just a month or so ago. Today, the air temp outside is 97 degrees. My engine temp is running right around 200 degrees. Normally it runs around 180. The air conditioner puts out minimally cool air, NOT COLD. It cools better at highway speeds than while driving around town. It seems that the higher the engine temp goes, the less the ac cools. I checked the refrigerant level in the ac last week and it was right at 52 psi according to my gauge...I think 55 is the high limit.

Here's what has me confused. No matter how hot the car gets or how high the ac is turned up, only one coolant fun runs. When I first crank the car, the fan on the passenger side of the radiator will come on briefly, but turns slowly, then turns off to never come back on again. Driver's side fan runs from the time you crank the car until after the car is shut off.

Should both of these fans be running under the conditions that I described above? And...if one of these isn't working, could that cause my ac not to cool as well as it should? I'm confused at this point...any help is appreciated!!

when the ac is on both fans should be running.you may have a bad sensor,try starting the engine with the ac off,let it idle & see if the drivers side comes on when temp gets to 220 or so.if not the ect sensor could be bad.
(engine coolant temperture)

[teafreak35]

Originally Posted by inafogg

when the ac is on both fans should be running.you may have a bad sensor,try starting the engine with the ac off,let it idle & see if the drivers side comes on when temp gets to 220 or so.if not the ect sensor could be bad.
(engine coolant temperture)

The driver's side fan runs all the time, now. It's the passenger's side fan that come's on for a few seconds at a very slow speed then turns off and never comes on again. If I'm understanding correctly, what your saying is that the driver's side fan may be coming on b/c the ac is on, so if I leave the ac off and it never comes on, then I've got a sensor problem?

[inafogg]

need to see a wiring diagrahm,i thought that the drivers side fan controled engine
temp & the passenger side fan comes on with ac.either way the fans should not be
running all the time,could be a sensor but also may be a wiring problem.has there been any accidents with the car or do you no if the fan has always been on.if you disconnect the ect sensor it should turn the fan on,thats why im thinking it could
be in the wiring.hopefully someone will have a diagrahm & crime in
BTW have you look at the fuses in cab & engine compartment?

[teafreak35]

Ok, here's some updated information. I started the car with ac off and engine cool. BOTH fans came on and ran UNTIL I turned ac on...then passenger side fan turned off. I shut car off and restarted engine with ac off again. This time, Driver side fan came on and stayed on and passenger side came on for a second or two then shut off and never came on again. Shut the car off a third time and let it set for a minute or two. Cranked it back up. Neither fan came on. I let car idle for about 7-8 minutes and watched water temp. Temp got to around 180, but never went over. Ideas?

[teafreak35]

Originally Posted by inafogg

need to see a wiring diagrahm,i thought that the drivers side fan controled engine
temp & the passenger side fan comes on with ac.either way the fans should not be
running all the time,could be a sensor but also may be a wiring problem.has there been any accidents with the car or do you no if the fan has always been on.if you disconnect the ect sensor it should turn the fan on,thats why im thinking it could
be in the wiring.hopefully someone will have a diagrahm & crime in
BTW have you look at the fuses in cab & engine compartment?

The car has not been in any accidents. all fuses are good and relays don't appear to be burned or anything. Where is the ect sensor? And...will it cause both fans to run or just the engine cooling fan?

[inafogg]

ect sensor is next to the thermostst housing.it only controls the one fan & should come on at 220* +/-

[inafogg]

hey tea,are you the original owner of the car??

[procaddytech]

Both fans should run any time fan operation is requested. They run in series for slow speed and in parallel for high speed.

I would suspect the mode relay first.

[teafreak35]

Yep, bought her new off the lot back in 99. Been a dream of a car all these years. I've never had any problems, other than one little coolant leak. This ac thing has me confused though b/c the ac system looks nothing like any of my other gm vehicles. There's no condensor or evaporator (that I see, anyway). If I understand right, it makes use of the radiator somehow...and I guess that's why the fan activity is having such an affect on the old girl...

[teafreak35]

Originally Posted by procaddytech

Both fans should run any time fan operation is requested. They run in series for slow speed and in parallel for high speed.

I would suspect the mode relay first.

So if one fan is running, at any time, they both should be running? If that's the case then there's definately a problem. If one of the relays is bad, would it cause one fan to sometimes work, but not always? Is there a way to test the relays?

[inafogg]

Originally Posted by teafreak35

So if one fan is running, at any time, they both should be running? If that's the case then there's definately a problem. If one of the relays is bad, would it cause one fan to sometimes work, but not always? Is there a way to test the relays?

do a search on youtube alot of info/test on relays
like procaddy says both work together,but if there is no fan command
neither should be on.
btw this is new to me its not the normal set up i've seen or im use to

[teafreak35]

Ok, after looking at the wiring diagram, I think I have this figured out. It looks like the PCM sends a fan on command to RH fan module...which then flows through the mode module to run LH fan (both on low speed). When both fans to be running on high speed, PCM sends signal to mode module which grounds out feed from RH fan and, at same time, engages the LH fan module so that both fans now run at high speed. After looking at this, I believe that my left hand relay module is bad. That's why the RH fan runs at full blast ALL the time and the left hand only comes on when engine temp is low and signals low speed! If this is correct and replacing the module fixes this...then you guys are my heroes!! Going to find a part...

[procaddytech]

If the left fan runs on low speed so sould the right fan. PCM grounds fan control ckt., closing relay 1. (any time fans are needed relay 1 is grounded and closed) Power comes from Cool Fan 1 fuse, through Relay 1, the L/H fan motor, up through the normally closed contacts (87A) of the mode relay, down to splice into ckt 532, through R/H fan motor to G103. They run series, 6 volts each, half speed. The Mode relay and Relay 2 are not commanded on until high speed is needed, isolating the L/H and R/H fans to each run on their own full 12 volts. With a cold start engine and A/C off, neither fan should be running.

[procaddytech]

Low speed operation: