fans won't come on!

dave40614 · #1 10-02-2005, 03:15 PM

99 grand am 2.4L, just finished head gasket job. All looks fine, except coolant fans won't come on ( I ran it three clicks past 200 F still nothing). When I turn the AC on the fans come on, and stay on after the AC is turned off.
Anyone know how to test this system ( relays, sending units, etc...)
Thank you,

coneyman75 · #2 10-04-2005, 07:52 PM

Quote:

Originally Posted by dave40614

99 grand am 2.4L, just finished head gasket job. All looks fine, except coolant fans won't come on ( I ran it three clicks past 200 F still nothing). When I turn the AC on the fans come on, and stay on after the AC is turned off.
Anyone know how to test this system ( relays, sending units, etc...)
Thank you,

On the drivers side of the block, next to the power sterring pump the is a plastic outlet which looks like a thermostat housing. Coming out of that outlet at the southeast direction is a brass fitting with a cannon connection. This is the temp sensor for the fans. I'm not sure of a way to test it but it is aa cheap part and easy to replace.

xeroinfinity · #3 10-05-2005, 12:54 AM

the fans should come on around 230 deg. First I would check all the wire plugs on the fans system. To test the fan to see if it has power coming to it, unplug the fans and test the plug with a light probe or volt meter. if theirs power to the fans(and the fans you said did come on) i would think it is the temp sending unit . I forget what the reading for the sending unit would be, the perameters.

gmack221 · #4 10-06-2005, 10:07 AM

I also would start by replacing the temp sensor on the water outlet. That most likely is the problem with the fan, if it runs with the A/C the motor is good.

You mentioned you just replaced the head gasket, did you also replace the water pump? What caused your head gasket to go bad? The water pump is hard to replace since its on the backside of the motor, but if you replaced the head gasket the water pump probably needs changed, its one of those preventive maintence things, you already had problems, keep those problems from getting worse! (cracking a head)

vamc · #5 10-07-2005, 02:35 PM

I dont think anybody said anything about and fuses, i guess i would check that as well as what everyone else has stated.

dave40614 · #6 10-08-2005, 11:58 PM

Quote:

Originally Posted by vamc

I dont think anybody said anything about and fuses, i guess i would check that as well as what everyone else has stated.

temp sensor checked out with ohm meter, all fuses are good, and the relays all check out good. think I did not wait long enough for fans the come on (230F).

vamc · #7 10-09-2005, 04:32 PM

hmmhmmmm. Bad cpu? i doubt it.

iamsodamnconfused · #8 10-10-2005, 03:03 PM

You mean the fans are not supposed to come on the second the car is started??? If thats the case, then I gotta problem!

gmack221 · #9 10-10-2005, 03:29 PM

The fans only come on when the car is started if you have the a/c on. Other then that they should come on when the motor reaches 230 deg. Fans running too much isn't near as bad of a problem to have as not running, you just might have to wait a while for heat in the winter, my guess is either for some reason your car is telling the fans the a/c is on or someone wired it directly to the fuse box (or power).

Anyone know of a simple reason why the fans would come on all the time? Is your temp light on, or gauge read really hot? either one of those two might turn on the fans, and if thats the case I would think it could be a bad sensor.

xeroinfinity · #10 10-10-2005, 11:30 PM

just because the temp sensor has an ohm run ok. it still may not be working properly. there are two relays, one for each fan and two fuses. does sound like almost the ac clutch relays stuck, making the car think the ac is on. goul luck

iamsodamnconfused · #11 10-11-2005, 12:09 AM

Quote:

Originally Posted by gmack221

The fans only come on when the car is started if you have the a/c on. Other then that they should come on when the motor reaches 230 deg. Fans running too much isn't near as bad of a problem to have as not running, you just might have to wait a while for heat in the winter, my guess is either for some reason your car is telling the fans the a/c is on or someone wired it directly to the fuse box (or power).

Anyone know of a simple reason why the fans would come on all the time? Is your temp light on, or gauge read really hot? either one of those two might turn on the fans, and if thats the case I would think it could be a bad sensor.

I dunno if this could cause it or not, but I do have a Viper remote starter installed on my car. I have noticed that I can turn the key to ACC, I can turn my blower on in the car, and my gauges power up. Is it possible they may have wired it for the fans to always stay on? The temp holds stedy at 200 degrees, maybe 215 if im stuck in traffic.

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