One mod I wish I had never done for sure!!

OK. Rant over.

My problem is that my efans work sometimes, others they dont. I can see in the HPT Scanner that the PCM is commanding them on. I can hear the relays click when I manually turn them on via the scanner, but the fans don't come on.

I let it sit for a day or so, and they came on and worked fine. Fast forward a week of it just sitting, and now they don't work again at all.

I can apply 12v directly do the fans and they work just fine. They are grounded well.

Any ideas what it could be? I'm using a factory harness and factory fans...I had hoped this would make it a trouble free install, I was wrooooong.

 

Well you started with voltage to fans and work good. Now just use a test light and check a o ower possibles. If pcm is commanding them on then check to see if power at relay then check power after relay check at fan plug if test light works power side is good make sure your ignition wire has good power as well. U can use test light to check ur ground side as well just. Im thrown as many options I can think of off hand

 

Like he said, just start checking where you have and dont have power. From the sound of it, I would guess you have a wire that is either broken or loose and making intermittent contact. I guess just give the harness and connections a good look over and see if you see anything damaged or loose.

 

All connections are solid and there are no broken/frayed wires. I've got it pulled out of the truck now. ha

I'm getting power at the relays. But to one of the power wires, I am only getting 3V. Is this correct?

I've attached a pic to illustrate what I mean.

 

If your relay clicks and nothing happens, you have bad relays.

 

I've swapped them with known good ones. And I have 12 v in the wires coming from the relays, this should rule out bad ones?

 

Should be no 3v on a efan setup should be all 12v. Check ur ignition is it a constant 12volts. Im lookn at ur pick I can see red is main 12v whats your yellow and gray go to and 2 small blue wires

 

You've got a voltage drop somewhere between 12v source and where you measured the 3 volts. Or a ground issue.

 

Pull the relays out.
Now jump pins 30 to pins 87.. If the fans work. then your relays are bad. If they dont work then check all your grounds and power connections.

 

Got it figured out. Thanks for all the help guys.

They weren't grounded well enough. Same ground I have for the headlights, and they worked. Go figure. Moved the ground and they worked fine. Almost melted the motor over a ground