Radiator Fan Problem

[tdubbs09]

Two weeks ago I replaced my radiator fan motor because the fan wasn't kicking on and the car was overheating. Well now the new one looks to have gone bad. It is an aftermarket motor.

Basically I was wondering if its just bad luck and the new one went bad, or is there possibly is another reason for the motor to burn up again. Maybe a voltage problem or something?

 

[wmburns]

What model year car are we talking about? Which engine?

Are you positive that a single speed fan hasn't been used in a dual speed application?

What have you done to check power to the fan? Check the grounds? Fuses?

How do you know the replacement motor is burned up?

 

[tdubbs09]

It's a 98 gt 4.6L. The plug has power. I'm not sure if it was a single speed or dual-speed. How can I tell? Also the ground seems to be fine. I get voltage between the hot and ground. No blown fuses.

 

[tdubbs09]

The replacement came with the assembly as well. It looks like the plug has 2 hots and a ground/neutral. So is one hot a high-speed and the other a low speed?

 

[COramprat]

Yes...one for high speed and one for low. One speed will come on as the car gets to operating temp and the other when you operate the AC. Can you get a jumper wire and operate the fan? Can you turn it by hand?

 

[tdubbs09]

Yes it will turn by hand. I will try and get a jumper and see if it will operate. Another thing is the plug looks like it has melted where the black wire is.

 

[tdubbs09]

Ok ....... So I put power to the motor and it worked, so it's not the motor this time. The thermostat was changed out 2 weeks ago. Could it be a loose connected ground/neutral (that's the black wire correct?) in the plug. Why would it work for 2 weeks and then stop?

 

[wmburns]

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.

 

[tdubbs09]

I just got back in from testing the power. It seems the high speed has power but the low speed doesn't. The fan motor itself is fine. I brought power to it from the battery. It's the red that is not receiving power. I kept the rpm's around 2,000 and let it heat up. The orange came on when the temp gauge was about 3/4 to red but the rd never came on. Then the water started to spill out.

 

[wmburns]

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.

 

[tdubbs09]

I believe the problem is in the plug. I ran it today to check power again. While the car was running I jiggled the plug and magically the fan came on. I turned the car off then started it again. The fan didn't come on, so I jiggled the plug again and the fan started. Thanks for your help guy's. If this doesn't fix the problem I'll be back.