I have the dual cooling fans in my car and unfortuneatly when i bought the car neither were in operating condition. So me and my buddy went thru everything inch by inch and rewired and rewired again and tried this and that and we could only get 1 fan to kick on and only when the AC was on. So right now im rigged to a switch to turn them on and off from inside the car. Any ideas please???


thanks guys

DJF

 

so u never replaced any sensors yet?

if not i would really look into the coolant temp sensor, that basically tells the computer the coolant temp and when the computer reads 225 ish the drivers side should come on.

the passengers side fan relay seems to be working since the a/c pressure switch seems to be working, but it doesnt seem like the fan switch is working unless of course the car never gets to around 234 ish the only time the passengers side fan would come on with the a/c being off.

swap relays real quick to verify the passengers side comes on with the a/c so u know u have at least two working relays and maybe sure both fans work also.

the coolant temp sensor should be in front of the engine. try some of those suggestions and see what u get.

 

the drivers side fan is the fan that works with the ac on, both relays work and the ecm is telling both relays to give the fans power because when i turn the ac on both relays get power but only 1 fan will spin

 

so have you ruled out the passengers side fan working with 12 volts right to it?

so does the drivers side fan come on after the engine sits and idles for awhile?

 

nope nothing comes on after idle or at any temp just when ac is one the 1 fan comes on. and both fans spin wired to a switch to 12 volts.

 

welp its my computer. i got it fixed so now the drivers side fan kicks on at the right temp and also when the ac is on. but the part of the ecu that kicks the passenger side on with the ac and at another temp is broke so i have that fan hooked up to a toggle switch completely volt free. when i turn the switch on it grounds out the relay and kicks on the second fan when needed. voila! works for now till I get a new ecu i guess.

 

It's NOT the ECM driver if the primary fan runs with AC request. Primary fan is driven by a driver IC in the ECM, aux fan by AC pressure switch in parallel with a coolant temp switch in the block. Before you replace the ECM I would do some more investigating.

 

the driver side kicks on at the right temp and with ac the passenger does nothing thats why i have the switch right now

 

Pass side fan won't run unless AC head pressure gets to a certain point, or the temp of the engine reaches 234 degrees. Pass fan is ONLY controlled by a single sender on the pass side of the block and the AC pressure switch. You may not have the right conditions for the pass side fan to run.