Corsica Radiator Fan Not Working....PLEASE HELP!!

[Oli_Oli_Umphry]

I'm working on a 1992 Corsica and the radiator fan will not come on.

This is what I have done....
Replaced fan motor. It works as I have tested it.
Replaced Fan relay twice.
Replaced Coolant Temperature Sensor.

I get power going to the relay, but none comming out for the fan wire. If I jump the wire, The fan comes on. Replaced the relay again thinking I might have gotten a bad relay. Still nothing.

This is driving me nuts. This shouldn't be that difficult. It's a freeking fan for god's sake!

Any help would REALLY be appreciated.

Thank's in advance.....Rick

[jsgold]

I have not dealt with this, but, my 91's service manual mentions a fuse (number 9 on mine, unsure on yours) and also a fusible link which feeds your relay. Might check that, although I believe you said you had power at relay? There are a variety of tests mentioned but these are for checking out the components ans especially the wiring from and to all( ECM, fan, sensor, relay). I do not know if mine is the same but if you want I think I can fax the pages to you

[Oli_Oli_Umphry]

Thank you so much for your reply.
Yes if you could email me the wiring diagram or anything relevant, Don't have a fax. Do you have a scanner? I would certainly appreciate it. I bought a Haynes repair book that stink's unless you want to change plugs or oil.
Let me know.
[email protected]

[jsgold]

Do not have a working scanner here, let me see if I can send it from work Tuesday. Will let you know if any trouble.

[Oli_Oli_Umphry]

Thanks

[mcrosby]

There are at least four wires going to any relay. Two of them are control wires from the computer that energize the coil. The other two wires are to complete the circuit to the device, in this case the fan, and allow the device to run. You may have power at the relay but the relay is not being "told" to come on. It may be tricky, but see if you can identify the coil connections on the relay by unplugging the relay and ohming out two of the contacts. The coil contacts will measure more than a relay "normally closed" contact. That is, a relay contact should measure 0 to 5 ohms depending on how good your test leads are and how good of a connection there is at your probes. A coil will measure 20 to 150 ohms dependant upon what type of relay it is. When you determine which contacts are the coil, find the connectors in the pins/socket, that correlate to these contacts and test for 12 volts DC across those pins. If you don't have the voltage, the relay is not being energized and the problem is "before" the relay.

Hope this helps

[Oli_Oli_Umphry]

Sorry it took me so long to reply.

Thank you jsgold for the documents. They were a great help allowing me to trace the wires and to isolate the problem.

As it turns out.....the grounding wire comming from the ECM, going to the relay isn't grounding. I haven't quite figured this totaly out yet as I don't quite understand why a grounding wire would be comming from a control unit, but the wiring for the cooling system is routed so many ways that it took me two days just to figure out where I'm at.

And mpcrosby's help was useful as well. Between the two, I should have this fixed by this weekend.

Once repaired, I will post with details so anybody with this problem will know exactly what to do.

[ksyankee]

I am having the same problem with my '94, I found the relay, and when I ground the green wire from the PCM the fan runs....I have replaced the engine temp sensor, are there any others that might affect the fan? the A/C is out of freon, but that shouldn't affect it coming on, if the car is getting hot?

Fuses are all good too.....J

[George_Costanza]

Originally Posted by ksyankee

I am having the same problem with my '94, I found the relay, and when I ground the green wire from the PCM the fan runs....I have replaced the engine temp sensor, are there any others that might affect the fan? the A/C is out of freon, but that shouldn't affect it coming on, if the car is getting hot?

Fuses are all good too.....J

I replied to another just a few minutes ago. sounds like you are having the same issue. Here was the text from my other post.

Originally Posted by CARLA WRIGHT

hi/91 CORSICA JUST STARTED OVEWRHEATING. REPLACED COOLANT WITH NEW, REPLACED THERMOSTAT, CHECKED FUSES. I NEED TO KNOW WHERE TO FIND IDENTIFY THE OTHERS--INLINE FUSE,RELAY,SWITCH. I SEE THE FAN AND I THINK I CAN REPLACE IT MYSELF/. PLEASE HELP!!!

I take it that your fan is not turning on and that is the source of your overheating. I have the same issue with my 92 Corsica, just diagnosed it.

I'm not certain what tools you have available but I started with a test light (12v dc) There are a couple of things that you need to check. Start with the relay. Stand in front of the car, with the hood open. look in the back left corner, right near where the big bundle of wires goes through the firewall. There is a group of relays, mounted sideways. The relay you want should be the closest one to the firewall (passenger compartment). It has a red wire with black stripe, pink wire with black stripe, I believe the other three are black, green, ?? (can't remember). disconnect the wires from the relay. there is one plastic clip on the side of the relay that you have to lift and then gently pull back on the wires. do not pull on wires real hard. about the same pressure as unplugging an appliance from and outlet.

with the ignition turned on, motor warm but not over heating. Car should not be running, just turned on during testing. Hook one end of your test light to a good ground. I used the negative terminal of the battery (on the other side of motor) to ensure ground. with the electrical tester, probe the contact on the end of the black wire, it should not light up. probe the end of the red wire with black stripe. It should light up. probe the pink wire, it should not light up, but I bet it will.

The other end of the pink wire is connected to your coil pack, bolted to the front side of the motor (where all the spark plug wires go). This is the piece that would need to be replaced, if the pink wire has power, when the motor is warm.