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Discussion Starter · #1 ·
were there any gm heater fans that ran the opposite direction than others? i have a full size truck and i think the heater fan is running backward from what it should,i dont remember if i ever changed it out or what i took it out of. it seems like it might be pulling air away from the core and then around through the duct. i havent checked this yet but if there were any fans that ran a different direction id know what to look for.
 

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runn141 said:
were there any gm heater fans that ran the opposite direction than others? i have a full size truck and i think the heater fan is running backward from what it should,i dont remember if i ever changed it out or what i took it out of. it seems like it might be pulling air away from the core and then around through the duct. i havent checked this yet but if there were any fans that ran a different direction id know what to look for.
Not positive but many 12 volt dc motors will reverse if you reverse the polarity. Ed ke6bnl
 

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Car? Truck? Who Cares
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Any DC motor will run in either direction.
All ya gotta do is switch the leads.

As for the motor in the truck----when the blower turns, it should pull air into the center and blow it out thru the outer circumference.

This truck have only one wire going to the motor???
I'm asking because I THINK mine does----under the hood.

Bryan
 

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Discussion Starter · #5 ·
Bryan59EC said:
Any DC motor will run in either direction.
All ya gotta do is switch the leads.

As for the motor in the truck----when the blower turns, it should pull air into the center and blow it out thru the outer circumference.

This truck have only one wire going to the motor???
I'm asking because I THINK mine does----under the hood.

Bryan
yes, it has one wire
 

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Doc here, :pimp:

If yours is a SINGLE wire motor...

It would be very hard to reverse directions without a major short, as the body of the motor will be hard ground..(reversing it will put 12 volts on ground!), So I doubt that has happened.

You might try checking the blower doors, for in-op condition or stuck doors, In AC mode it will be opposite of the heat mode on door positions..

The door motors may be Vacuum, Electrical, OR mechanical (cables) , Chances are pretty good this may be where the problem lies.

To test if it is blowing or sucking, just place a source of smoke in front of the vents and see what way the smoke goes.

Doc :pimp:
 

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docvette said:
To test if it is blowing or sucking, just place a source of smoke in front of the vents and see what way the smoke goes.
Doc :pimp:
If the heater fan is a squirrel-cage type, which they generally are, it will always push air in the right direction, even if they are turning backwards. This is because they are centrifugal, they use the centrifugal force acting on the air to "fling" it outwards from the center. Granted, the fan will not work very well turning backwards, but it will blow air in the right direction.
 
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