Cooling Fans Not Turning On

Ok see here is the deal. My car is overheating while sitting at idle because my fans aren’t turning. So I know why my car is overheating, now I need to figure out why my fans aren’t turning on. It’s not the relay because the AC works. Not sure if there is a fuse or anything that can go bad or not. So I took it to my buddy who works at a Honda dealer and he looked at it and tested the power wires and all and they were getting power. The only weird thing was when he checked them both wires were getting power. He checked them at the connector of the fans and I guess the main harness on the passenger side. When he put the test light down into the socket both wires made it light up. Now assuming one wire is a hot wire and the other is the ground wire, he thinks it could be a ground problem, but in order to track that down he needs an ETM to figure out which wire is which and and where it is supposed to be grounded. So that’s where I am at right now. If anybody knows where I can find some schematics of how the cooling fans and all are wired it would be greatly appreciated and if anybody has anymore insight as to what to check for that would also be appreciated.

I’m not 100% convinced it’s not the fan switch. I asked if it could be and he said no. Any help is appreciated.

[QUOTE=DAtIntegra35;2164902]Ok see here is the deal. My car is overheating while sitting at idle because my fans aren’t turning. So I know why my car is overheating, now I need to figure out why my fans aren’t turning on. It’s not the relay because the AC works. Not sure if there is a fuse or anything that can go bad or not. So I took it to my buddy who works at a Honda dealer and he looked at it and tested the power wires and all and they were getting power. The only weird thing was when he checked them both wires were getting power. He checked them at the connector of the fans and I guess the main harness on the passenger side. When he put the test light down into the socket both wires made it light up. Now assuming one wire is a hot wire and the other is the ground wire, he thinks it could be a ground problem, but in order to track that down he needs an ETM to figure out which wire is which and and where it is supposed to be grounded. So that’s where I am at right now. If anybody knows where I can find some schematics of how the cooling fans and all are wired it would be greatly appreciated and if anybody has anymore insight as to what to check for that would also be appreciated.

I’m not 100% convinced it’s not the fan switch. I asked if it could be and he said no. Any help is appreciated.[/QUOTE]

Mine didn’t work, I took off the ground for the relay(on driver side below headlights in front of radiator) sanded it down and the spot where it was bolted too and they work fine now. Maybe try that.

Yeah I guess it wouldn’t hurt to try that.

Sand down and clean the ground on the themostat housing, just above the fan switch. The fan switch will not work if that ground is not made.
Despite what your friend said, unless he tested the fan switch then it could still be the problem. Take it out, throw it into a pot of hot water and test with an ohmmeter. Switch should close when it gets hot.

[QUOTE=wise_old_dragon;2165001]Sand down and clean the ground on the themostat housing, just above the fan switch. The fan switch will not work if that ground is not made.
Despite what your friend said, unless he tested the fan switch then it could still be the problem. Take it out, throw it into a pot of hot water and test with an ohmmeter. Switch should close when it gets hot.[/QUOTE]

Thats actually not the ground for the fan of any sort.

[QUOTE=wise_old_dragon;2165001]Sand down and clean the ground on the themostat housing, just above the fan switch. The fan switch will not work if that ground is not made.
Despite what your friend said, unless he tested the fan switch then it could still be the problem. Take it out, throw it into a pot of hot water and test with an ohmmeter. Switch should close when it gets hot.[/QUOTE]

Well the fan switch is before the point that we tested in the circuit. If the fan switch did not turn on, then there wouldnt be power going to those wires correct?

That ground does in fact effect the fan switch circuit somehow. I have tested this myself. You can test this by jumping the fan switch harness with and without the ground. With the ground connected, key in on position, and the harness jumped the fans will turn on immediately. Unplug the ground, they will turn off.

The reason i know this was because i was changing out my fan switch and forgot to wire up the ground. My fans did not work until that ground was wired.