Radiator Fan Problem

At the moment I only have a 2002 reference manual. Therefore, some of the wiring colors may be different.

The two speed fan has (3) wires. The black is the ground. OG/LB is the high speed and RD/OG is the low speed.

A basic fan test is to use a jumpper wire from the battery directly to the fan. One wire from the black to ground. +12 volts to each fan speed terminal. There should be a clear difference in fan speed.

The fact that the black wire through the connector show signs of overheating should be looked into. This could be the results of dirt/grease in the connector. Clean with contact cleaner and re-grease with silcone di-electric grease (same kind used on spark plugs).

The connector may be beyond repair. The fan uses a lot of current therefore, the connector needs to be able to carry it without overheating. A connector replacement may be needed.

This could also be a frame ground problem. Check the battery. Is it clean? Are the terminals clean and tight? What about the frame ground connectors around the battery?

Seams plausible to me that the same thing has caused both fans to fail. However, it could be just plain old bad luck.

What if the low speed and high speed fan is engaging at the same time? I honestly do not know if this could happen. To test, check for +12 volts at the fan harness. Voltage should be present on only one lead at a time.

If there is voltage on both leads, we need to test/replace the CCRM.

OBTW, it may have taken 2 weeks before enough heat built up to actually melt and damage the connnector.

Just so we are clear, only one lead should have power at a time. The LS and HS fan should not be engaged at the same time.

From your description, it sounds like the LS fan is not working. This does not make sense. One would think that if the LS fan were in-op, then it would get hotter quicker but cool once the HS fan kicked in.

There is a small separate fuse box on the right hand engine compartment. This contains a separate fuse/circuit breaker that powers/protects the low speed fan. Check for power coming into the fuse/CB. Consider injecting +12 volts into the output terminal to see if the low speed fan starts.

Is it possible that the fan has been wired backwards (at the fan motor for example)? Can you hear a difference between the LS and HS modes?

Let's say that the HS/LS fan has been reversed. Then when the PCM called for LS fan, the HS fan would run instead. This would overload the LS fan circuit breaker. Fan stops. Engine continues to get hotter. PCM calls for HS fan. However, the LS fan runs instead. The LS fan does not move enough air to cool the engine. Nor would it move enough air to keep the AC from shutting down due to high compressor head pressure.