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Intermittent Blower Fan


dr fildo

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99 AWD 5.0 Mountaineer

The blower (HVAC) works... Occasionally. When it feels like it. Today it was 100° outside. No blow. Tonight, works fine.

I'm assuming that if the fuse blew, it wouldn't work at all.

The rear blower works, and the air is cold from back there, so the compressor is working.

Anyone have a guess?
 


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1998Exp

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The blower (HVAC) works... Occasionally. When it feels like it. Today it was 100° outside. No blow. Tonight, works fine.

I'm assuming that if the fuse blew, it wouldn't work at all.

The rear blower works, and the air is cold from back there, so the compressor is working.

Anyone have a guess?
Is it manual control or EATC?
 




dr fildo

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Manual. And I replaced the switch about 6 months ago.
 




koda2000

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Have you tried tapping on the blower motor (from the engine compartment) when it fails to run? If it starts running after tapping on it the motor is bad. You should also unplug the motor's electrical connection and check for dirt and corrosion.
 




dr fildo

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I haven't tried that yet. I will do that when it fails the next time. Which should be later today, because it's supposed to be very hot today.
 




koda2000

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I haven't tried that yet. I will do that when it fails the next time. Which should be later today, because it's supposed to be very hot today.
In my experience, intermittent operation is pretty common for bad 12V electric motors. As they age the brushes wear and don't make good contact. Hit a bump in the road or changes in temperature can be just enough to bump them to life and they'll continue running until the next time they're shut off. I've had this happen with convertible top motors, many fuel pumps and blower motors.
 




Turdle

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jlrohio

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Have you tried tapping on the blower motor (from the engine compartment) when it fails to run? If it starts running after tapping on it the motor is bad. You should also unplug the motor's electrical connection and check for dirt and corrosion.
In my experience, intermittent operation is pretty common for bad 12V electric motors. As they age the brushes wear and don't make good contact. Hit a bump in the road or changes in temperature can be just enough to bump them to life and they'll continue running until the next time they're shut off. I've had this happen with convertible top motors, many fuel pumps and blower motors.
Koda2000 is correct in his assessment of the blower motor and simple testing technique.

Below is a link to an old thread I had on the same issue with a video of me tapping on the blower motor and hearing it run after being tapped. For me, changing out the motor worked in my case. There are video's on YouTube that cover this repair.

http://www.explorerforum.com/forums...ther-blower-motor-thread.428102/#post-3427500
 




bobflood

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+1 on blower motor. Just had the same thing happen w my '97 EB. Replacing blower motor pretty easy on this vehicle. Unbolt the cruise servo; move the coolent/WW fluid bottles, plenty of room to R&R the blower motor. Good luck.
 




dr fildo

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Ok, it seems to be the blower motor, which I already have out. I'm having trouble getting the plastic fan wheel off the motor.

Any helpful hints on how to get the plastic fan wheel off the motor without breaking it?
 








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