I'm working on my neighbors car and the cooling fans won't come on. The fuse and relays are good,but I am not getting the ground from the computer to activate the relays. Does anyone know where the coolant temp sensor or the computer is located? Or has anyone had this problem?

Thanks,
Will

 

i would say its not the temp sensor does teh car show it over heating on the cluster?? if it does then the temp sensor is doing what it is suptose to be doing showing the temp of the engine. Now on to the fan part here is the diagram of the system U could have a blow fuse,messed up wire,there are 2 relays.fans themself can be shot,or the pcm.

[IMG]local://upfiles/51666/C1AC0E1A72144095B47BD1D6A9471B2B.gif[/IMG]

 

If I understand right these cars have a coolant temp sensor for the gauge and one for the cluster. I already stated that the relays, fuses, and fansare good, as well as the wiring from the relays to the fans. The problem that I am having is the computer is NOT supplying ground to the relay. The fans come on if I supply ground to the proper relay terminal. So, back to my original question, does anyone know what tells the computer the engine temp?

Will

 

there is only one temp sensor if what u see on the cluster is correct then that is what the computer sees. Thats why i asked u if teh cluster is showing it over heat or not. If the cluster does not see it over heating then yes sensor if it shows the temp to be over heating then the sensor is working as it should.
Now back tot eh grounding of teh relays which one have u grounded high or low side? And all u are doing is juming teh power to the fans and not supplying the ground on teh PCM side or are u? and then which side low or high because as u can see there are different wires and drivers for high and low.

 

I have applied ground to both the high and low relays and the fans come on. The cluster reads about one third of the way from cold and the car boils over and will not let the A/C engage. The car never turns the fans on no matter how hot the car gets or how much it boils over. With ground applied to the fan relay the A/C does work normally and I get a check engine light for code P1489 which is for the High Speed Fan Relay Control Circuit, because I am grounding the high speed fan relay.

Will

 

ok then replace the coolant temp sensor there is only one

 

OK, sorry, I was misinformed. I did a little research and found that you are correct and there is only one sensor.

Thanks for the help,
Will