Need some help with learning how the electric fans are wired up. Does anybody know how they work? Thanks for the help!

 

Dude....use the search button...there is about 100000000 post about this!

 

If you can read a schematic, it tells most all.

 

Thanks for your help shoebox!!! If your 95 PCM pinout is similar to a 94 PCM then I lost the connection between the relay box and the PCM. Does anybody happen to know where line is routed? Thanks!!

 

94s and 95s are virtually the same. The relay control wires route from the PCM along the RH shock tower to by the battery, in front of the radiator and to the fuse/relay panel on the LH side. Your C100 connector will be closer to the lower mount for the RH hood strut.

 

Ok Now here's the clincher. I looked at that C100 harness to find a perfect connection to the relay box. However, when I look at the RED connector "A" on my PCM pins A10 and A11 don't have continuity between the relay box or the C100 connector. This isn't normal is it?

I looked at the wires running out of there and was about ready to scream. Where is the connection between the PCM and the rest of the system routed? Any hints?

Thanks!!! You've been a great help!

 

The wires should go from A10 and A11 directly to C100. Have your fans always acted this way? Did you just buy the car? Did someone else modify the wiring? Do you understand how to prove continuity from C100 to PCM connector A?

 

Nope no modifications. Actually, I just rebuilt the motor. After putting it back in the car. No more fans.

I can explain the symptoms:

1. Short pins in ALDL connector with data logging equipment. Normally, this forces fans to run all the time. Now if this is done with ignition on motor not running, engine will not turn over. If ALDL port is shorted after car started. Car runs fine w/o fans.

2. Car gets to temp. No fans what so ever. Upon scanning PCM no faults are registered.

3. I tried the trick to test the temp sensor by grounding it. Car wouldn't start.

4. Turn on A/C still no fans.

5. Trace all connections. Relay box is golden, fans are golden, all the way back to C100 connector which is still golden. Then the A10, A11 pins link between the RED connector A on the PCM and the two pins on the C100 connector is no continuity.

I just used a multimeter continuity check between the PCM and C100. Is there something special here? Shouldn't there be a hard wire between the two? If so Is it in that mess of cables just behind the PCM?

Thanks!

 

If you used one meter lead on the A10 or A11 in the harness plug and the other meter lead on the corresponding green or blue wire at C100, you should see good continuity on the wire. Your meter should be set on continuity or ohms and you should see close to zero ohms (like if you touched your meter leads together). If you have no continuity between those points, you need to expose the wiring and find out why.

 

Yikes... Thanks... I'm gonna have to dig into that now.

 

There's an update. I'M A MORON!!! Checked the continuity with the C100 connector unplugged. Thus there was no connection between the PCM and the relay box. With it plugged in as it should be my connections are fine.

Now, I have verfied that all my Fan wiring is cherry, fuses are good, and relays are perfect.

How do I check the temperature sensor? Unplug the sensor and short the two leads on the harness? (I noticed one was ground). When I tried this my car would not start.

Thanks for the help!!!!

 

Ok now I'm getting really frustrated. Bought a new sensor for the water pump. Still same story. Does anybody have wiring schematics for this sensor? I noticed when logging the PCM that the temperature never changes.

Thanks!

 

Info on testing the temp circuit.

 

Well I tested the temp circuit. It is functioning properly as well. Is it possible there is a poor connection in the line to the PCM and yet I have voltage? Where does this patch into the PCM harness? Thanks for your help!

 

Well, I got it narrowed down to something in the temp circuit. However, I don't know how this wires back to the PCM to trace the broken connection.

Does anybody know how I can just wire up the relay to turn my fans on when the car starts up? I would like to do a temporary fix for the time being. It would be nice if it's something I don't have to do any splicing / cutting of wires to do too.

Thanks for the help!