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Old 10-20-2010, 12:52 PM
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Wierd (?) blower motor issue

Just a quick introduction since this is my first post: My name is Jeff and I live in LA (Lower Alabama). I just bought a 1999 GC Laredo (4.0, 2wd) for $800........not running. Got it running, cleaned up, replaced all brakes (turned all rotors), shocks and tires and it is a nice vehicle.

I have searched a ton of the old blower motor threads but mine seems a little different.

Problem: Intermittent blower motor operation.
Facts: Blower motor works perfectly on all speeds once removed. Connections look good (not melted or corroded).
Issues: Blower typically does not work when you start the vehicle. Tap the installed motor a few times and it will get up to selected speed.......but not stay there for long.
Tried: Took blower motor out and operated connected to harness....worked perfect on all speeds. Checked for obstructions in chamber......seems clear. Removed clip holding fan on motor....still could not get fan off. Cleaned fan, lubed shaft put clip back on and reinstalled. Same problems and issues.

This has apparently been happening for some time as the bottom of the blower motor is bashed in a little bit.....plastic housing cracked and scuffed.

It does not seem to make sense to replace the blower motor since it works fine when not mounted and dangling on the wire harness. Also does not make sense to replace the resistor since all speeds work.

Any similar experiences or helpful suggestions would be greatly appreciated!!!

Jeff
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Old 10-20-2010, 02:49 PM
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Re: Wierd (?) blower motor issue

There are no visible signs of chafing of the fan in the housing or any abnormal noise when the fan is installed? The fan also works normal when its not mounted, but kept in the same position as if it was mounted?
Did you move the motor wires by hand when installed, to check for internally broken wire?
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Old 10-21-2010, 06:49 AM
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Re: Wierd (?) blower motor issue

Did not see any rubbing inside or abnormal noises. I did NOT however hold the fan in the upright position when i had it out. I held it sideways....not sure if it was just more convenient or the harness was too short. I also did wiggle the wires and connection point with no apparent difference.

I will pull it out again this weekend and check everything again. I do see how holding the fan upright might just put that little bit of added pressure on the motor bearings.

I am guessing the "whacking" either frees up the bearings for a moment thus letting the motor spin faster or somehow aligns the stator/brushes momentarily to make better contact. Just guessing though!!

Thanks for the help!!!
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Old 10-21-2010, 10:34 AM
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Re: Wierd (?) blower motor issue

Did you turn the fan by hand in the normally mounted position to see if there is any binding or roughness in one of the bearings?
I have never opened the fan motor, but it can be that the brushes are worn or sticking.
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Old 10-21-2010, 07:48 PM
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Re: Wierd (?) blower motor issue

Yes, i spun the fan in the upright position and it seemed fine. However very slight bearing damage can go undetected yet cause problems in my past experience.

I did notice today that as the fan blew hard (after slight tapping) it seemes as though there is not even flow. The passenger side seems to be getting less air (very weak on high), the vent on the right of the steering wheel blows good and the one on the left of the wheel blows very little on high. I am wondering if there isn't something caught up in there somewhere.

Is there a good (simple) way to check out the duct work for obstructions?
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Old 10-22-2010, 08:30 AM
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Re: Wierd (?) blower motor issue

Are you sure that the outlets are all fully open? If you close the outlet with the higher flow, will the flow on the other outlets increase a lot? Makes it any difference when in recirculation mode? When you put in defrost, do you have a lot of air on the windshield? And when you put it on feet?
There can be ofcourse some obstruction in the ducts, but it will not be easy to access the ducts, as far as i know.
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Old 10-22-2010, 12:50 PM
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Re: Wierd (?) blower motor issue

Quote:
Originally Posted by Frango100 View Post
Are you sure that the outlets are all fully open? If you close the outlet with the higher flow, will the flow on the other outlets increase a lot? Makes it any difference when in recirculation mode? When you put in defrost, do you have a lot of air on the windshield? And when you put it on feet?
There can be ofcourse some obstruction in the ducts, but it will not be easy to access the ducts, as far as i know.
I am not sure. I will check it all out this weekend. With variable air volume issues is that possibly a blend door problem? I will have to see if there is any way to check according to my Haynes manual.
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Old 10-22-2010, 03:27 PM
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Re: Wierd (?) blower motor issue

Does your car have the manual airco/heat system or the AZC? In the last case there will be 2 blend doors in the system and that could maybe give some flow difference. The manual system only has one blend door and should not make any difference in airflow. But the blend door is in fact only routing the outside air or direct into the car, or via the heater core ( in fact the door will be mostly somewhere in an intermediate position to mix outside and heated air ). But when a low temperature is selected, just cold air (depending on what the outside temperature is ofcourse) should come out and the heater core is bypassed.
If you have the AZC system, you could run a system test to see if there is any fault stored in the system.
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Old 10-25-2010, 07:16 AM
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Re: Wierd (?) blower motor issue

Nope..........no AZC.

I did pull the motor again this weekend and got TOTALLY different results. The only way I could make the motor work on all speeds was to tap on the bottom of it (motor unmounted). It also sounded all rough and scratchy this time. Definitely getting a new motor!!!

I also checked the duct work as far as I could reach and it seemed clear. Was a bit wet inside which seems unusual since the car had not been used for 12-14 hours. I do need to blow out the AC drain because it is leaking on the passenger floor board. I tried sticking a piece of wire in the drain tube (engine cavity 4.0) and got nothing.

Thanks for all the help and I will report back on the new motor.
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Old 10-28-2010, 06:54 AM
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Re: Wierd (?) blower motor issue

New blower motor and all is well. Patched cracked duct work and no more leaking on the floor boards. Woohoo..........thanks for all the help Frango!!
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