cooling fans quit working
Thread Starter
Instructor
Joined: Aug 2003
Posts: 148
Likes: 0
From: Mitchell, Indiana
cooling fans quit working
So it appears that both my cooling fans have stopped working, and I believe the fuse is not blown, just curious if anybody can give me a good start on where to look. Maybe one of the relays? Any good way to diagnose a bad relay? Both quit at the same time. Trying to get them working before thanksgiving so i can drive it home from school and park it for the winter. All your help is appreciated!
Melting Slicks
Joined: Dec 2004
Posts: 3,284
Likes: 51
From: Jacksonville, FL
St. Jude Donor '08 thru '26
Do you have a wiring diagram, like in the Helm FSM? I would start with the fuse(s)? Then fab up a jumper set and discon the fan plugs and provide a ground and a hot and see if each one works. If they don't then ya know what's up. If they do, then the FSM may have a diagram of each relay, using that you could test each relay.
Also, I know that there is a program in the ECM that also controls the fans when the HVAC system is activated. I have a 90 and I know that there are a few ways the fans are controlled. Oh, forgot this, the fans need a signal from the water temp sensor thru the ECM as part of the circuit in my 90. That sensor is separate from the water temp sensor that drives the temp gauge on my 90.
Start with the simple stuff first. Maybe a big auto parts store has a relay tester and they might test the the fan relays for free. I bought a relay tester when I got my C4 as I'm not all that great with electricial stuff....I'm way slow & it takes me too long to "get it"!:o
Tom
Also, I know that there is a program in the ECM that also controls the fans when the HVAC system is activated. I have a 90 and I know that there are a few ways the fans are controlled. Oh, forgot this, the fans need a signal from the water temp sensor thru the ECM as part of the circuit in my 90. That sensor is separate from the water temp sensor that drives the temp gauge on my 90.
Start with the simple stuff first. Maybe a big auto parts store has a relay tester and they might test the the fan relays for free. I bought a relay tester when I got my C4 as I'm not all that great with electricial stuff....I'm way slow & it takes me too long to "get it"!:o
Tom
