hey guys. i'm having this annoying problem with my car, that after reading on here some i see i'm not the only one either.
my car is a 98 GT coupe sunfire and my car is overheating at times when sitting due the fan not coming on. back in december the temperature sensor for the gauge and cooling fan failed, causing the fan to constantly stay on and not letting my car warm up in 25 degree weather and snow. Ever since i've had the car, which is about a year, if the a/c is not on, the fan doesn't come on...period! lol. i've had that gauge go as high as one centimeter from the "red zone" before i had to finally turn the a/c on to cool off the motor. I've replaced the cooling fan relay, temp. sensor, and fan motor (which has made the fan run stronger when it IS on). My question is.. what else is there that tells the computer or fan to switch on to cool the car off??! It's getting annoying having to constantly watch that temp gauge in traffic!! Any ideas?
other than that this car is amazing!!
well the fan has a negative switching relay (think thats the terminology). basically, when temp reaches a predetermined point, the ECU switches something internally and allows the relay to have a path to ground, completing the circuit.
its possible that the problem lies within the ecu or the wiring. you may not have 12VDC going to either the control or motor side of the fan relay or its possible the ground side of the relay is bad for either the control or motor side. if neither works, or you dont want to deal with it, set up a manual cooling fan switch. there are lots of threads on it and can be done with either an extra relay or by adding a switch and a diode. (search and you shall find, the switch and diode way is less wiring and is in the electronics section).
have fun.
1997 Cavalier Z24 - 15.647 @ 88.02 MPH
sorry to semi-threadjack but I'm having problems with my cooling system as well. It runs and then burns out fuses. I have bypassed it and the same thing, it burns out after sometimes days of operating normally. soooo either 1)i have a short that happens randomly at the fan motor... or 2)too much load on fan motor
i spin it by hand and it feels like its spinning fine.
to the OP were you able to buy just the fan motor and how much was it??
If your fan comes on with the AC on but not by itself then I would think the problem is in the temp sensor signal. the control side of the circuit must work since the AC switch turns on the fans.
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<<<<<2003 Sunfire Sedan>>>>>
whitegoose a lot of what you said makes sense. I did have the wiring system checked out by a local diagnostic shop and was told that the wiring is all intact and that he thought everything under the hood looked very good actually that he thought "the whole thing's workin fine. I cant find anything wrong with it." lol. So if the wiring is indeed good like he said, this must mean the ECU since i have a brand new temp sensor and fan relay.
i did forget to add one thing. if i go outside in the morning and start the car and let it idle to normal temp, the gauge will go to just below center, where it normally is during driving, and once it gets to the center, the fan comes on.. but if i drive on the highway then get stopped in traffic or sit waiting for a train crossing then the gauge will keep climbing until i switch on the a/c on. i dont know if this sheds any light on anything.
and to answer your question adam, you can just buy the motor which would run you around $25-$30 or you can get the Fan Motor Assembly which comes with the fan, shroud, and motor already assembled for $150-$200. but if your blades and shroud are fine you should be fine with just the motor.
I would replace the fan motor connector this simple and cheap thing solved my last overheating problem...
Was it difficult changing the fan motor. What advice to you have for me since I am going to be doing this tomorrow I think?
Thanks - Brad
Fan relay and ECU ground are working correctly if the fan comes on by turning the A\C on. When your computer sees a request for A\C, it grounds the same fan relay as it does for overheating. So it is good.
The problem might lie inside of the computer. It sounds that it is not commanding the fan on when it hits the pre-programmed parameters (like 225 degrees).
Could be a coolant guage problem too
lol.
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www.bradsairsoft.com
wow.. i haven't been on here in a while lol. well the problem was my ECU very unfortunately! after posting here, we had a very bad storm and lots of flooding. No, Sonny didn't get flooded out, just was perceived as a duck for a day or two with all the water i had to drive through. After this storm my ETS/ABS was disabled, car was very hard to start at times, and the "Theft" light kept coming on and off. My ECU was being destroyed at a snail's pace basically. For some unknown reason, the ECU to my car is basically mounted underneath my car inside the bumper on the front passenger's side instead of somewhere like say ohhh..INSIDE THE CABIN! Also, I was unaware that I had a section of the inner splash shield missing so everytime I drove through water my ECU was getting a nice bath....Thanks GM! :\
Hey my cooling fan wont stop blowing, even when the car is off, i replaced the relay and it still wont shut off, any ideas?
