I have replaced all coolant relays and components and my cooling fan will not work unless my ac is on.Any suggestions on how to fix or what the problem could be?

20

Asked by Aug 21, 2015 at 09:25 PM about the 2002 Pontiac Grand Prix GTP

Question type: General

Its also supercharged

13 Answers

69,315

Is the engine overheating? The fans will come on at low speed when the coolant temp reaches approximately 220°F. As the temp continues to climb the fans switch to high speed at about 240°F. If the fans won't come on at all have you replaced the coolant temp sensor? If so, it could very well be a faulty PCM. HTH. -Jim

Best Answer Mark helpful
20

Yes I replaced the temp sensor also and fans still aren't coming on

1 of 1 people found this helpful.
1,175

There are 2 temp sending units, one for the gauge etc., and another for the cooling fan control

20

I changed the one on the block where would the other one be

1,175

Probably near the thermostat, that's where it is on my 2000 GTP.

20

That's the one I changed it goes into the block by the thermostat

69,315

Not on this vehicle. One sensor for both the PCM and the dash gauge. HTH. -Jim

20

Thank you Jim

1 of 1 people found this helpful.
69,315

You're welcome. Glad to help. -Jim

1,175

If you have replaced the sensor, all the relays and "components", sounds like your going to have to trace the wiring. GOOD LUCK!!!

69,315

Since the fans will come on when the air- conditioning is on we know they can work. Without the air-conditioning on the PCM is supposed to complete the circuit to ground and start the fans. The PCM determines when to do this based on information it receives from the coolant temperature sensor. If anything it could be the wiring going to the PCM from the coolant temperature sensor. Otherwise it's most likely going to be a PCM problem. Ideally someone needs to plug into it with a scan tool and command the cooling fans on. HTH. -Jim

1,175

This is true, but if it were mine I'd check the wiring from the sensor to the PCM, heat and engine vibrations can cause a multitude of problems with small wires in tight places. Enjoy!!

1 of 1 people found this helpful.
4,175

You haven't mentioned whether the car actually overheats. The fans rarely come on on my '03. Maybe its just not getting hot enough to need them. Maybe you're trying to fix something that's not broken.

1 of 1 people found this helpful.

Your Answer

Grand Prix

Looking for a Used Grand Prix in your area?

CarGurus has 2,731 nationwide Grand Prix listings starting at $1,200.

ZIP:

Pontiac Grand Prix Experts

  • #1
    Js08016
    Reputation
    4,370
  • #2
    Tom Demyan
    Reputation
    2,970
  • #3
    munron
    Reputation
    2,350
View All

Related Models For Sale

Used Chevrolet Impala
588 Great Deals out of 34,659 listings starting at $1,000
Used Pontiac Bonneville
515 listings starting at $1,799
Used Chevrolet Monte Carlo
11 Great Deals out of 1,353 listings starting at $995
Used Ford Mustang
762 Great Deals out of 42,755 listings starting at $1,300
Used Pontiac Grand Am
1,091 listings starting at $1,599
Used Chevrolet Camaro
418 Great Deals out of 31,785 listings starting at $2,395
Used Chevrolet Malibu
1,230 Great Deals out of 78,092 listings starting at $1,500
Used Pontiac Firebird
12 Great Deals out of 814 listings starting at $1,900
Used Honda Accord
1,020 Great Deals out of 62,741 listings starting at $999

Content submitted by Users is not endorsed by CarGurus, does not express the opinions of CarGurus, and should not be considered reviewed, screened, or approved by CarGurus. Please refer to CarGurus Terms of Use.