2002 Cavalier A/C and Radiator Fan Not Functioning

[mjwomo]

The AC on my 2002 Cavalier has been out for about 1.5 years. I haven't messed with it much as I used to have another car that I drove most of the time, but not anymore. I really want to get the Cavy working properly. I checked all related fuses, and swapped the relay for the fuel pump with the ac and still nothing worked, so I am pretty sure the problem is outside of fuses/relays. Any help would be appreciated! Thank you in advance!

[J-Ri]

For the A/C, first check that it has refrigerant in the system. Not being used for long periods of time is bad on the o-rings and it cold have all leaked out. Auto parts stores sell low side A/C pressure gauges, the pressure in PSI should be roughly the same as the temperature in degrees Fahrenheit. If it's more than 15% different (I forget which way), there is a leak and you'll need to have UV dye added to the system to find the leak. There's really no point in adding those cans, because you know there is a leak if it's low. DO NOT add the refrigerant that has "stop leak" mixed in with it. It will plug up the A/C system and the A/C machine that the shop you take it to has. It's bad stuff.

For the fan, disconnect the connector to it and measure the voltage across the two terminals. It should be the same as the battery voltage when the fan is commanded on by the PCM. To get it to be commanded on, let the engine idle until the gauge gets up about 3/4 of the way. Don't let it get into the red, but it needs to be at least 222 degrees F for the fan to turn on. Gauges can be off by quite a bit, which is why I gave 3/4. If you have access to a scan tool that can command the fan on, use that, but most people don't. If you have voltage across the connector when the fan should be on, the fan motor is bad. A very common failure on the older ones, I haven't yet seen one on the 2000+, but I assume they are the same and just haven't started mass-failing yet. The motor is cheap, but a PITA to get the fan out, at least it was on the only one I have ever done ('97). Most people opt not to fix it, I don't know why, it's pretty important.

[jbayone]

I've got a similar problem. First noticed the air wasn't working and when I looked under the hood, saw the cooling fan wasn't either. It's overheated a couple of times since then so someone hotwired the fan at the relay box. Still no air though and everytime we stop, I have to open the hood to remove the wire to stop the fan. Any ideas? Let me know if you need any more info or what I can check for.

[thisnametooktolong]

Originally Posted by jbayone

I've got a similar problem. First noticed the air wasn't working and when I looked under the hood, saw the cooling fan wasn't either. It's overheated a couple of times since then so someone hotwired the fan at the relay box. Still no air though and everytime we stop, I have to open the hood to remove the wire to stop the fan. Any ideas? Let me know if you need any more info or what I can check for.

yep buy a book with a schematic in it and start tracing the problem with a noid light. after you get the fan fixed, start checking the A/C out. and try not to hyjack threads

[J-Ri]

Welcome to AF!

Please start your own thread for help, and remember to include the year and engine size.

[ollie31]

I had the same problem and it turned out to be the fan motor. It is a real pain to change and you have to be real careful that you dont puncture the radiator.

[Jmrec100]

To check it, run power to the fan. Connect a wire from the connector to the battery. If it turns on, motor is good, then somewhere before that at a relay(?),temp sensor, the computer, or wherever, its not getting a signal to turn on. I think Mine had a bad temp sensor-happened 3 years ago- I replaced it but still used the switch. Need the schematic. I haven't had the time to trace it. I had mine turning on so late, more than 3/4 by the gauge that I rigged a switch to mine and turn the fan on when I need it in the summer. But be careful NOT to forget. I am going to put a relay in it so I can run it with the computer and also can manually turn it on. Need the relay to turn off when the ignition is off. I forgot to turn the switch OFF a few times. That's why its nice to have a jumper battery.