I have a '92 Accord Ex. Cooling fan is not turning on and I can not figure out why. I have verified the following Jumpered the fan it runs. Confirmed relay good checked fuses=ok. Tested switches at thermo housing and outlet replaced both for good measure as both original to car over 250k miles. Fan runs when jumpered at switch plugs but still will not turn on when vehicle gets to operating temp. Fans also do not turn on when a/c is turned on. Any suggestions on where to go from here greatly appreciated.

 

Thanks for doing a lot of the work before posting.

I'd unplug the relay for the radiator fan. Look at the relay pins. Two will be a heavier gauge metal (I think they are copper or brass colored) material, this is the power side that goes to the fan motor. The other two pins will be the low current control side.

Use a volt meter on the sockets of the fuse box where the relay plugs in. One power and one control pin should have 12V when the key is in the II position. Use a good ground (-battery terminal or bare metal valve cover bolt) for you meter to do this testing.

The control socket that does not have power should switch from open circuit to closed circuit to ground when you turn on/off the a/c.

 

Is the A/C system working - meaning the compressor clutch engages when you turn it on.

Was there any work done prior to this issue?