Radiator Fan Help Needed

[Levitan]

I think this is a simple solution but I can't figure it out.

'96 Aspire, auto. Radiator fan doesn't come on.

Unplugged the single wire that attaches to temp sensor in front of block, the one that, when unplugged, fan should run. Does NOT run.

Unplugged fan from main loom, ran pos and neg to battery, fan runs.

Don't appear to have any juice from loom at plug.

Searched site, and discovered relay in front of battery behind drivers side headlight. Assuming it is one of the 3 relays under rubber boots. Found the one that I think it is, replaced. Still nothing.

Have spare car to remove and check parts.

Any help would be appreciated. Thanks.

[aspireguy95]

dan did you check the fuse under the hood?

[Levitan]

Yes, is good.

Come up here and help me fix this thing.

[blkfordsedan]

Use a volt meter to check for power at the plugs going into and out of the relay. If you have a Haynes manual, it should show you the wiring diagrams. Sounds like you have a bad connection somewhere. The plug at the fan that you just unplugged has a habit of getting corroded where the wires connect to the terminals inside the plugs. Try wiggling the wires where they run into the back of the plug ends.

[FB71]

Dan, got your PM. I'll need to consult my tea leaves and divining rods (wiring diagrams), and I'll see what I can determin.

[FB71]

OK, here's skinny;

the fan is PCM controlled. The PCM looks at the ECT signal (two wire sensor, the single wire sensor is for the gauge only) and turns the fan on at a calculated temp. the sensor wires are Violet/Green and Red/Blue, and the sensor is on the passenger side of the intake manifold. The relay has 4 wires. The White/Black wire should have power at all times, and the Black/White wire should have power when the key is on. The violet wire is the voltage out to the fan. The Brown wire is grounded by the PCM when the fan is desired.

Turn the key on, ground the brown wire at the relay, and if the fan comes on, the ECT sensor is the most likely culprit.

[Levitan]

You are the man, Jim! I will run diagnosis and report back.