Heater/AC Fan - doesn't blow most of the time

[B26Marauder]

I have a very high mileage 2000 Eddie Bauer. Over the last two weeks a strange problem has emerged. The Fan for either AC or heat does not blow. It never works when I first start the car. But 3 or 4 times it will just suddenly start working 20-30 min later into the drive. I can be driving, or sitting at a light, at the fan will just come on and start blowing like it's suppossed to. Once it does start blowing, I have full control and can adjust the speed successfully. It will also continue to work until I turn the car off and let it sit for 30 min or so. Some days the fan will just not work at all. I can still feel heat (or cold if it's AC) coming from the vents or floor, the control for where it comes from (Vent, Floor , defrost, etc..) works correctly, it's just the fan speed that is random. Is this probably a relay that sticking or something like that? Can't be a fuse because like I said, it will occasionally just come on and work like normal. Even selecting "Max A/C" does not cause the Fan to blow ....

 

[Turdle]

The problem is likely the blower motor relay--or, the blower motor resistor circuit.

 

[gijoecam]

Being an Eddie Bauer, it should have the EATC (Electronic Automatic Temp. Control... IIRC, it was standard on the limited and the EB) If so, you'll want to check two things: First, when it won't run, tap on the blower motor relay and see if it jarrs it loose. If so, replace the relay. (might want to replace it anyways just to be safe).

If that still doesn't work, pull the relay and check for continuity to ground through the terminal marked #85 in the relay receptacle with the EATC set to run. The EATC module grounds the trigger coil on the relay. You should have 12V at terminal 86 and a ground at 85.

If the relay is being triggered properly, you'll need to check the blower motor itself. Find the OG/BK wire coming off the motor and run a wire directly from the terminal to the ground. If the blower motor runs, we know the motor is good.

The only thing left would be the blower speed controller. It is controlled by the EATC module and regulates the ground to the blower motor to vary the speed.

Good luck!

 

[B26Marauder]

Gijoecam, thanks so much for the valuable info. I'll try those steps tomorrow and post the results. I don't have anything other than the owners manual for reference. Will that show me the location of the relay? How about the motor itself and the controller? Do I have to tear the dash apart to get to these?

 

[IS300M]

Anyone got the partnumber for the blower motor speed controller dealy?

 

[shamaal]

While your banging on things, consider tapping on the motor itself. That was my problem.

Good Luck!

 

[B26Marauder]

It was the blower motor itself

Thank you gijoecam, your troubleshooting steps allowed me to determine it was the motor itself. By the time I was able to troubleshoot, the fan had stopped working completely. It no longer came on randomly. I was able to find the relay and test the voltages, which were good. I also swapped the relay with another identical one that had the same part number, fan still didn't blow. I found the motor orange/grey wire and tried grounding it directly and still no fan motor turning. I knew then that the motor was bad. I was able to get a life-time replacement motor from Auto Zone for $40. It was a minor pain to move the cruise control, windshield fluid bottle and Air Filter housings all out of the way so that the fan motor could come out without interference. Works great now though.