mbradley2020

OK i recently put an engine in my 99 malibu and now my cooling fans do not work. It was my understanding most cars have 2 coolant temperture sensors one for guage and one for cooling fans. I have only found one temp sensor so far and have replaced it but no luck. I have my doubts that its the PCM because it worked fine with the old motor. I have tested relays and jumped power to the fan motors also checked most wires for continuity and everything works. Would it be possible to direct wire my fans to a ACC hot wire and let them run all the time? But if possible i would like for everything to work factory conditions. Any help?

rhandwor

Look around the thermostat housing on the intake.
http://www.ebay.com/ search 8040554745 This is a picture of one but it has part of the harness on it.
ECT sensor is what to ask for at the parts store. Pull the one from your other motor as it worked. Also check fuses before changing it out. As it worked before changing the motor the harness should be ok unless you pinched a wire.
Check that the fan motor was plugged in after changing the motor. Look at what was done as this should be where the problem is located.

brcidd

How do you know they are not working? are you red lining om temp gauge?
You can command them on with a Tech II- have you tried that yet? Is coolant overflowing into overflow tank? Sometimes it takes awhile of running to get engine warm enough to command fans on-- what do they do with a/c on? does a/c get high pressure cut-outs? from lack of air flow?

__________________
Automotive A/C Engineer with:

'95 Chev 3500, 454 Dually Crew Cab- 145k miles- Wife's Camel trailer puller.
'94 Astro- 370k miles
'94 Firebird Formula- 5.7L 180k miles- gone- blown head gasket
'92 Chevy Lumina Van 3.8L 264k miles
'86 GMC S-15 - 2.8L 154k miles
'86 Buick Park Ave 3.8L 199k miles- my daily driver
'77 Chevy Vega- 2.5L 175k miles gone but not forgotten
'68 Camaro 396 4 spd RS/SS -72k miles- my high school car!!

All but the Camaro and Firebird are white....

BernieMacDaddy

i have this same problem but my coolant does flow out of the overflow tank..just replaced head gaskets because of it and now i still dont know whats wrong, new water pump thermostat.. going to change the ect sensor tomorow, hopefully that"ll turn the fans on and solve the problem, any other suggestions?

jpmalibu

yea BernieMacDaddy i have the same problem but my car is 03 malibu .let me know if that fix your problem that i can do the same to my car.

rhandwor

Assuming the temperature gage works the fan should be running around mid range. One fan should start when the A-C is turned on. If over temperature tap the fan motor with a small hammer if it starts replace with a new unit.
You can use a 12 volt test light when hooked to the battery negative you should have 12 volt. When it needs to start hook up the test light to the battery positive touch the other side of the plug it should light. If you have both voltage and ground the fan motor should run.
You can swap relays between the A-C fan and other fan for checking.