Cooling Fans Don't Work

[ShariSings]

I have a Pontiac Grand Am Se, 4 Cyl:

The cooling fans don't work. I've tried replaced the sensor located by the thermostat but the fans still don't work.

[xeroinfinity]

Welcome to AF.

Check the fuses and relays.
The relays are on the pass side under the hood.
Should be 4 altogether, but I'm not certain which ones are what. I know one is for the fuel pump, the AC and the two others are for the Cooling fans.

If they check out I'd try using a jumper wire and test the fan motor(s) with direct current from the battery.

Also the fans will only come on when the engine is around 230 deg, or when the AC is turned on.

Hope that helps!

[CrimsonGlory]

I am having the same issue with my '03 Grand Am. It usually runs at the halfway mark on the temp gauge, but lately has been running up into the next quarter, but only when it's idling. I noticed that the fans weren't kicking in, but they do when I turn the A/C on. Checked all the fuses & relays in the fuse panels, checked coolant level, checked oil, thermostat is fine as it cools back down after the fans run a bit. Assume it's either the temp control or there is a sensor on the A/C that lets it bypass for the fans when A/C not in use. My husband just fixed the same issue on our '99 International tractor trailer. Will let you know if I have any luck!

[xeroinfinity]

-The PCM commands Low Speed Fans ON under the following conditions:

The engine coolant temperature exceeds approximately 106°C (223°F).
The A/C refrigerant pressure exceeds 1310 kPa (190 psi).
The vehicle is shut off when the engine coolant temperature is greater than 140°C (284°F) and system voltage is more than 12 volts. The fans will stay ON for approximately 3 minutes.

-The PCM commands High Speed Fans on under the following conditions:

The engine coolant temperature reaches 110°C (230°F).
The A/C refrigerant pressure exceeds 1655 kPa (240 psi).
When certain DTCs set.

[CrimsonGlory]

yep those are the temps but the fans weren't kicking in at all when they should have been. Turns out it was a bad connection at the temp control sensor. Working fine now, but past experience with overheating has taught me to err on the side of caution and figure it out quick. Or risk cracked heads! Thanks

[xeroinfinity]

Originally Posted by CrimsonGlory

yep those are the temps but the fans weren't kicking in at all when they should have been. Turns out it was a bad connection at the temp control sensor. Working fine now, but past experience with overheating has taught me to err on the side of caution and figure it out quick. Or risk cracked heads! Thanks

Sorry , check the wires was something I forgot

[CrimsonGlory]

No biggie also I had heard/read somewhere that the sensor for the oil down by the oil filter runs in the same wiring and can cause glitches... checked that one too, seeing as its lower where moisture can get to it pretty easy. Next on the list is to change the plugs and air filter seeing as it's running a bit rough.. only has 150 000 KMs (or 93,200 miles) on it . I've had it 3 years and never changed the plugs, so it's due!

[red88jeep]

This is just an FYI. The radiator sensor requires a minimum mix of antifreeze in the coolant to work properly. If you were to break a hose and refill with just water, then the sensors in the cooling system may not trigger the cooling fans or talk to the computer just right and give false information to the computers. This is because it is calibrated for a antifreeze mix verses a straight water mix. Had this problem when my wife broke a hose on her minivan some time ago and she only put water back in. She started complaining about over heating and she was not hearing the fan come on. I checked the fans and they were fine (the hot lead worked to the sensor, and when I jumped it, the fans came on.) I replaced the coolant with a 60/40 mix of antifreeze/water and everything worked fine. I later found buried in a manual somewhere that a straight water mix would cause this problem on this particular vehicle.

[xeroinfinity]

red88jeep, please look at the dates before you post in old out dated threads!!
We dont need to bring up threads older then 3 months.

PLUS you are wrong about the temp sensor!!!
It does NOT know whether the liquid in the cooling system is water or antifreeze.
I'd say the temp sensor is bad or not grounded or has a wire fraid..