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YACT - Another car problem - Help! Overheating

C

cornbread

Senior member
93 Olds Cutlass Ciera -
Overheats when Idle, fan won't cut on...
I replaced the fan motor with a new one, same problem - still won't cut on..
When the motor was hot i felt both radiator hoses and they were both hot, so I think that ruled out the thermostat..
According to the book, when that is done, if the fan still does not cut on, it says to check the computer for trouble codes since the fan is controlled by a cooling sensor and the ECM.. Checked out the computer, no trouble codes at all - system normal..
Any ideas? I'm wondering if maybe a wire has gone bad between the motor and whereever it connects to, but maybe one of you car experts have something else in mind..
Thanks in advance for any help!!

--Edit--
I also checked the fuse for the fan as well, it checks out ok, its tied in with the alternator.. I checked the other fuses also to be on the safe side, the ones that I could check, and they seem ok as well
--End edit--
 
Originally posted by: Pepsi90919
check the motor for operation, check for current at the wires on the motor, you know basic stuff.
Click to expand...

The new motor does work, tested that, but I'm not getting any current to the motor.. Sorry for not mentioning that..
 
Originally posted by: NutBucket
How about the coolant temp sensor?
Click to expand...

Haven't checked that yet, any way to test or see if it's good without replacing it?
Or is it one of those cheap things to replace?

Thanks you guys for the quick responses so far
 
Originally posted by: cornbread
Originally posted by: Pepsi90919
check the motor for operation, check for current at the wires on the motor, you know basic stuff.
Click to expand...

The new motor does work, tested that, but I'm not getting any current to the motor.. Sorry for not mentioning that..
Click to expand...

Is there a relay for it somewhere? If you have a wiring diagram for the system, which i assume, start checking stuff. Relays and sensors do fail.
 
Originally posted by: NutBucket
Originally posted by: cornbread
Originally posted by: Pepsi90919
check the motor for operation, check for current at the wires on the motor, you know basic stuff.
Click to expand...

The new motor does work, tested that, but I'm not getting any current to the motor.. Sorry for not mentioning that..
Click to expand...

Is there a relay for it somewhere? If you have a wiring diagram for the system, which i assume, start checking stuff. Relays and sensors do fail.
Click to expand...
Will do that tomorrow.. Any idea about how much a new cooling sensor would cost? Just a rough guess

 
I was going to suggest that the cooling temp sensor may certainly be bad. A replacement sensor should be pretty cheap for your GM. A Napa "Echlin" brand replacment was about $12 for my Saturn. At that price, it's not much of a gamble. It did the trick for me.

Question: If you've still got working AC in this car, does the cooling fan come on when you turn on the AC?

If the AC does work, yet the fan does not turn on with the AC compressor, forget the temp sensor, and go for the fan relay.
 
First, apply 12 volts across the new fan motor and ensure it turns.

Once you know the fan motor works, start going back through the system.

I'd put good money on a bad relay. Take out the relay and short the pins that form the on/off switch for the fan motor. If the fan spins, get thee to an auto parts store and buy a new relay.

If that doesn't work, check or replace the coolant temp sensor.

For all of this, I strongly suggest that you arm yourself with a service manual for your car. 'Twould make things a lot easier.

Edit: Thegongale has better troubleshooting tips than I do. I didn't read the thread through before replying.
 
I have a couple questions, then I can help you.

1) Did the fan come on when you tested for codes?

2) Does the fan come on when the A/C is turned on?
 
Originally posted by: cornbread
Originally posted by: NutBucket
How about the coolant temp sensor?
Click to expand...

Haven't checked that yet, any way to test or see if it's good without replacing it?
Or is it one of those cheap things to replace?

Thanks you guys for the quick responses so far
Click to expand...


All you need to do is have the key in the on position for the car. Pull the wire off the coolant fan switch, and ground it to metal. If the fan comes on then you prob. have a bad coolant fan switch.

 
Originally posted by: Quixfire
I have a couple questions, then I can help you.

1) Did the fan come on when you tested for codes?

2) Does the fan come on when the A/C is turned on?
Click to expand...

ooh, forgot about that. GM OBD-I turns on the fans when in diagnostic mode.
 
If you can't figure out the problem from the above advice, just rewire the fan so it's always on when the car is on.
 
Originally posted by: DrPizza
If you can't figure out the problem from the above advice, just rewire the fan so it's always on when the car is on.
Click to expand...


Do NOT do this. I see this at my shop all the time, this is just asking for MORE problems.

 
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