my fans have recently stopped working. This became obvious when we were tuning the pcm, and it failed to kick the fans on during the pcm read. The fans never came on during the test drive either. Fan Motors appear ok and I even hooked up a new motor, but still nothing. I hate electrical work, but did my homework and traced the lines to the pcm (blue and green), they have power. All three relays check out fine, and verified when put in the foglight slot to test operation. I noticed relay one and two both recieve power when key is turned on, in pin slot #4 for each, but relay 3 does not get any power from its pin 4? Should it, and how exactly does relay 3 work when it comes to fan operation. When I did the field test, using a jumper wire between pin 5 and 6 under the dash at the computer hook up, I understand that the fans should kick on, but they don't, I do however here an audible click. Any ideas, and is there a fusable link somewhere for the fans, exact location would be usefull. Thanks

 

Have you tried hooking up another motor when you do the jumper wire test to confirm that current is getting through the wires?

One of my friends had a bad temp sensor harness on the water pump and his fans wouldn't come on.

 

Hi. You didn't mention what year or car you have but you should check all the fuses in addition to the relays. There are at least a couple fuses in the underhood fuse box that you should check. I discovered my fans weren't working either and it was due to the #7 underhood 25A fuse that is for the air pump/cooling fans. I haven't had the air pump recall done on my car so i unplugged the air pump connector and the cooling fans work normal now and the fuse doesn't blow. So I'm pretty sure the air pump is bad. By the way, my car is a 96 OBD 2 and I never got an SES light, and even now with the air pump unplugged I don't get an SES light. Shoebox has a good cooling article on his website. If no one provides a link for it, I will post it later when I have it handy.

 

my car is a 95. Yea, had the new motor hooked into primary 1 when I did the under the dash jumper test, nothing but the click noise. All fuses are good too.

 

Info for the cooling system...

 

question for you, the diagram really helps, maybe my problem is the one labled Red 402, has a fuse link, but says goest to "B+", what is that exactly? Does that mean, battery positive? The diagram makes it look like that fuse link should be close to the underhood fuse box, but I suspect it is closer to the battery, or the positive accessory point just behind the battery. There are plenty of visible fuse links there?