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Yes you can, that is my standard test to check the blower motor

FYI, top fan speed is direct, no resistor, full battery voltage across the blower motor.
 

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When resistance goes up on a ground circuit, the amperage also goes up on the delivered power circuit. With higher than normal amperage, the electronics get stressed even with the fuse still functioning.

If some piece of electronics keep failing every few weeks, look at the quality of the grounds and actual electrical connections for high resistance issues.
 

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Yes you can, that is my standard test to check the blower motor

FYI, top fan speed is direct, no resistor, full battery voltage across the blower motor.
Thank you. I thought that was the case, but didn't want to burn something up in the process of trying to diagnose something.

Thanks!
 

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Same issue on my friend's 2004.
It lost them all at once. The resistor was only a year old. All speeds went at once. The connectors look good.

My question is if I can run a hot and a ground direct to the blower to make sure it's not the problem without frying the fan. It could end up being a temporary fix until it warms up next week, because we are already getting snow and a defroster would be handy.
so what blower resistor did you buy ? part #, store ? etc....
 

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Hi. A couple weeks ago the resistor died for the heater fan on my wife's 2004 Silverado. I bought one at the local parts store for $65.00 because I needed it in a hurry. It made it two weeks and now it is cooked again. The black ground wire in the plug that plugs into the resistor is also burned. I suppose if I buy another resistor it will work for a while before burning out again, but I think there's something else wrong. The 30a fuse is fine. I took the old red and black wire from the fan and plugged them into the harness that plugs into the resistor to get some heat for now. I'd welcome any thoughts. Thanks.
Napa sells a pigtail. All the wires are white on it but if you note the position of the connector lock, cut and splice each wire one at a time you'll have no problem. Remember to offset each splice as to avoid a bulging ball of tape all in the same place.
 

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The blower motor may be on it's way out. When the bearings fail it starts pulling too much current which eats the resistors and connector.

Ted
 

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I was replying to Keemo830's post at 2:28 this morning. I guess you could call it old if that post got to you before it got to me.

Ted
 

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Sorry so late on this reply! I've changed many resistors and pigtails without changing the motor. I don't recall ever having to replace a pigtail that I've already replaced or a blower motor shortly afterwards. I have also changed blower motors due to bearings going bad but I've usually could hear the bearing or feel it in the dash. Also, not that I've noticed but I don't recall having to replace the pigtail or the resistor after replacing a blower motor due to a bad bearing which I've changed plenty of those also.
 

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The pigtails are a little on the small side. I don't think I've ever seen one with heavier gauge wire.

Ted
 
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