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blower motor randomly starts

metulburr

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04 buick lesabre custom
Ive noticed that when i start the car, the blower motor will sometimes not work at all. Then when i hit a speed bump or pot hole it starts working immediately. This is a reoccurring event.

After researching online, other comments from other vehicle types say that it could be a defective blower motor resistor. Where is this located on the buick lesabre 2004? Or could this be the blower motor itself?
 
Last edited:

imidazol97

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You can trouble shoot with the fan speed on any speed.

If you get in the car, turn the key to ON, and don't hear the fan start up, put your leg across the hump and tap upward against the bottom of the dash in front of the left passenger foot position. The fan is a circular item that does not have a plastic shroud over it, so you can tap it with your foot. If it starts the fan blowing from the vibration, that means your fan motor needs replacement. The contacts on the armature are stuck or the armature is corroded or worn.

You can get down on the floor of the passenger side to look in advance of doing this.

But the bumps on the road cause the carbon contacts on the armature to complete the circuit from the vibration through the corrosion.

You do not say if you have a Custom or Premium model. I'm not sure that even the Custom uses resistors after 2000. I'd have to check my service manual.

The only other place your problem could be is the connection block a few inches from the blower motor where the contacts snap together. Some of those overheat from a poor connection giving more resistance which leads to heat at the connection. The plastic around that contact is weakened from the high heat and doesn't hold the connection together like it should, leading to more poor contact and more heat from resistance.

You can squeeze the connector in various ways when the blower is NOT blowing even though the key is OH, and the contacts may connect starting the blower again.
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metulburr

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04 buick lesabre custom
Thank you for the information. I will try those out the next time it stops working to diagnose it better. By the way, it is a custom model. Again, thank you for your post. It was very helpful and gave a lot of points to try.
 

G-574818

To the poster with the erratic blower:
Does the blower work on other speeds when it is running?

I read the post to indicate that the times it's not working are when the car has been off and the blower motor (or the connector) has cooled. The cooling on mine apparently let the commutator lose contact with the carbon brush. The commutator on the armature was rough and grooved, but the carbon block that's the contact did NOT slide easily in its groove. So the thing wore while running and then shrank away from the commutator when stopped. Then when I'd start the car again, there was no circuit through the blower motor until a bump or the vibration from my shoe caused the carbon brush to move or the armature to move.
 

metulburr

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Buick Ownership
04 buick lesabre custom
Yes the blower works on all speeds when it is running. When it is not running, it doesnt work on any speed, including high.

Since posting this i havent had it not work at all...go figure. Before this, it was not working 50% of the time. Ive been keeping my eye out for it to not work to try some things.
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imidazol97

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Just be prepared for when you start your car and the blower doesn't run. Then try the tap test. Then another time try reaching from the passenger side up to the connector and see if squeezing and moving it makes the connectors work inside again.

If the blower works on all speeds when it is running, then I think it's a connector or the blower motor itself.
 
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