a/c blower motor problem

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Sep 27, 2009 | 01:26 AM

knitebee

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a/c blower motor problem

I've got an '83 F150 with factory A/C. For some time now when ever the heater selection switch is on A/C or any setting that cycles the A/C (defrost, mix) the blower motor will start bogging down after its been running for 20-30min. If I kick the selector over to "vent" or "heat" setting the fan will be back up to speed within a minute or two. The resistor pack test good. Being an issue that doesn't start tell its been running for a while has made it very incovienent to try and diagnose the cause. Any ideas of what to test and how?

Brian

Sep 27, 2009 | 08:54 AM

Brooksd1991

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sounds like your blower is going out. It still has a little life left, but they arent too expensive and if you dont wanna waste your money plenty of salvages have them.

Sep 29, 2009 | 12:02 PM

knitebee

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#1 I just replaced the blower motor and the problem is the same.

#2 the problem is only there on a setting that engages the A/C

Sep 29, 2009 | 12:19 PM

1986F150six

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From: Sheffield, AL

Is it possible that the evaporator core is icing up, thereby restricting the air flow?

Sep 29, 2009 | 03:14 PM

knitebee

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Quote:

Originally Posted by 1986F150six

Is it possible that the evaporator core is icing up, thereby restricting the air flow?

Certain that isn't the case, you can even hear the blower motor bogging down. Of course ever time I drive far enough to have the issue I either dont have the time or volt meter with me to get more info.

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