1993 Grand Prix SE 3.1 coolant fans

[bob rutledge]

my daughters 93 Grand Prix is overheating. The fans will not cut on at all. I have run it in my driveway until at the red and no fans. When I cut the AC on the fans will not come on either. Even if I put AC at max and blower on high no fans. I can jumper them and they will come on so the fans are good. Could this be the temp sending unit? Also her blower motor has stopped working as well. Putting the blower motor on high does nothing, the blower does not blow any air. Could this be why the coolant fans are not coming on when I put the AC on max and the blower motor on high? Just throwing that out there. Any ideas appreciated.

[bob rutledge]

As a side note the blower fan has been on its way out for a month and has finally died.

[94GrandPrix]

my daughters 93 Grand Prix is overheating. The fans will not cut on at all. I have run it in my driveway until at the red and no fans. When I cut the AC on the fans will not come on either. Even if I put AC at max and blower on high no fans. I can jumper them and they will come on so the fans are good. Could this be the temp sending unit? Also her blower motor has stopped working as well. Putting the blower motor on high does nothing, the blower does not blow any air. Could this be why the coolant fans are not coming on when I put the AC on max and the blower motor on high? Just throwing that out there. Any ideas appreciated.

 

Are you jumping the fans directly to the battery? If that's the case and they turned on and they don't come on with any other action (turning on the AC, when the car is getting hot, etc.) then my first guess would be the fan relay(s).

[RobertISaar]

fan relays(or their wiring/fuses) or the ECM's temp sensor(or its wiring). considering that neither fan comes on, I would suspect the temp sensor(2-wire) first, otherwise fan 2 should have kicked on a bit before hitting a high enough temp to get the guage into the red. having both fans suddenly quit working at the same time isn't likely.

 

the fan that turns on due to a/c request will only turn on if the compressor is bringing the system pressure high enough to warrant extra airflow. it's possible you have a dead a/c pressure sensor as well, or your compressor isn't actually engaging or able to bring the system pressure high enough to hit that threshold.

 

otherwise, you're dealing with a possibly faulty ECM or your dash guage/sender is faulty.

 

if you had access to a scanner(especially one that allows mode 4 controls) you could rule out a lot of these.

[bob rutledge]

Are you jumping the fans directly to the battery? If that's the case and they turned on and they don't come on with any other action (turning on the AC, when the car is getting hot, etc.) then my first guess would be the fan relay(s).

 

I jumped the fans through where the relays are. removed the relay and jumper end 3 and 5.

[bob rutledge]

fan relays(or their wiring/fuses) or the ECM's temp sensor(or its wiring). considering that neither fan comes on, I would suspect the temp sensor(2-wire) first, otherwise fan 2 should have kicked on a bit before hitting a high enough temp to get the guage into the red. having both fans suddenly quit working at the same time isn't likely.

 

the fan that turns on due to a/c request will only turn on if the compressor is bringing the system pressure high enough to warrant extra airflow. it's possible you have a dead a/c pressure sensor as well, or your compressor isn't actually engaging or able to bring the system pressure high enough to hit that threshold.

 

otherwise, you're dealing with a possibly faulty ECM or your dash guage/sender is faulty.

 

if you had access to a scanner(especially one that allows mode 4 controls) you could rule out a lot of these.

 

Correct on the AC pressure. The compressor is not kicking on as it is low on freon. Yes I know I have a bunch of stuff going on with this car.