2002 Pontiac Grand Prix GTP cooling fans not working

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wwlrak
Posts: 1
Joined: Fri Jun 23, 2017 7:01 am

2002 Pontiac Grand Prix GTP cooling fans not working

Unread post by wwlrak » Fri Jun 23, 2017 7:07 am

OK i got a 2002 GTP. the cooling fans will work if i unplug them and jump directly from the battery, all fuses are good. I took a 20amp fused jumper and jumped the cooling fan 1 relay from pin 87 to pin 30 and i get a click that comes from under my air box. I believe the engine computer is there. Not sure if i jumped the relay right or not not the best with electrical issues. Any advise is much appreciated. I,m stumped and can,t afford to take to shop

 

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carriedi
Posts: 2280
Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: 2002 Pontiac Grand Prix GTP cooling fans not working

Unread post by carriedi » Sat Jun 24, 2017 12:32 am

not working as in the temp gauge gets to the red and the fans are still not running? Or does it just get higher than normal and no fan yet? Does the fan come on when you turn on the ac?


your low speed fan should turn on at 223f
ac fan comes on at about 190psi

high speed fan should come on about 230f
and high ac fan at 240psi

scan for codes. scanner will also show you if there is a fan request or not.

there are three fan relays and two fuses. cool fan 1 relay has power from the cool fan 1 fuse. cool fan relay and cool fan 2 relay both get power from cool fan 2 relay. All the relays get the signal to turn on from the powertrain control module when the temp get hot enough or the AC needs it.

Is your vehicle running warm? Is it because of warmer weather or do you actually have a problem with overheating?
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1Daddio

Re: 2002 Pontiac Grand Prix GTP cooling fans not working

Unread post by 1Daddio » Sun Jul 16, 2017 8:04 am

I also have the same problem an my code comes up as broken ground? To where an what an how do I fine it to fix

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carriedi
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Joined: Wed Apr 10, 2013 12:42 pm
Location: Oregon

Re: 2002 Pontiac Grand Prix GTP cooling fans not working

Unread post by carriedi » Wed Jul 19, 2017 2:47 am

If your car is the same as the one in the diagram the ground wire for the fans and the fan relays are the same. the black wires that go to the ground connection lower left front of engine on the transaxle stud by the starter.

I have tools that plug in and bypass the relays to see if there is a good circuit for the fans to come on at the relay connection. Ir's a good way to see if everything is good on that end of the circuit. Yhen I have relay adapters that go in for the relay and the relay plugs into the adapter. Each prong on the relay is now accessible and I can see what the relay is getting or not getting. Those tools along with the scanner that tells me engine coolant temp and if the PCM is requesting the fan relay on or not ate all important tools to check the operation of the fans.

If it is just a ground problem you could always make a new ground for the circuit if there is an open in the circuit and you can't find where the break is

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