HVAC Blower issues

[Reluctanse]

2000 K3500-
My blower motor is working inconsistently. I'll get in the truck, and no air is coming out. The controller itself is lit up, and the blend door controls are working, I can hear them when I move the selector. However nothing will come from the fan- totally dead. Then, and randomly, it will start working. Once it works, all the speeds work. But once its working it stays working for the drive, and possibly even next time I get in the truck. Then after overnight sitting, it won't work again, until it randomly starts while driving.

I haven't pulled anything apart just yet, is there a connector on the control module that is JUST for the fan that is possibly loose? Or any other ideas what I should chase down?

 

[bluex]

I thought mine in the z71 was a bad blower or resistor back in the day. Turned out to be a burned up plug on the fan speed switch. It let the pin get loose an intermittently contact. Check that first imo.

 

[HotWheelsBurban]

So...if the blower motor does not work on any speed, most likely the motor or switch? Blower motor was making more noise than I thought it should, and I think (was not riding in the front seat so not entirely sure) the last day or two that it did work, wasn't moving much air. It was really freaking hot though those days....
Supposed to be back into triple digits in Houston soon, ugh. Humidity is great for keeping your hair curly and your skin softer, but other than that it sucks!

 

[Reluctanse]

what is up here?

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Is this for something my truck doesn’t or did the pins get pushed in some how?

 

[east302]

If the wire colors match that connector, it looks like it’s for rear defrost.

A dead blower is often a melted connector at the blower switch as bluex mentioned. To test, you’d check for voltage at the first three fan speeds at the resistor and high at the relay connector. Part number for that is below if you need a new one.

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Blower:

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[Caman96]

If the wire colors match that connector, it looks like it’s for rear defrost.

A dead blower is often a melted connector at the blower switch as bluex mentioned. To test, you’d check for voltage at the first three fan speeds at the resistor and high at the relay connector. Part number for that is below if you need a new one.

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Blower:

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@east302 you always bring your “A” game.

 

[Reluctanse]

thanks guys!!

strange the wiring harness even though I don't have rear defrost.

went to the treasure yard today and got another controller with harness so I should be able to get it back up and going with that, hopefully..

now, I'm wondering if I could get a suburban controller with rear defrost and use that to control my heated mirrors... side project!

 

[pressureangle]

Though all of the wiring considerations above are known issues, don't reject the possibility that your fan motor is simply tired. An old guy showed me the trick 40 years ago (should have been obvious tho) to drill a tiny hole in the point of the metal fan motor housing and give it a few drops of 3-in-1 or other light machine oil. The back of the motor is a simple bronze bushing and they get dry and sticky- you'll be amazed how much better an old fan blows. Still, it can be simply worn out brushes from age and constant hot-climate use.

 

[Reluctanse]

Well its not the control module. Swapping that did nothing. Per usual I should have done some better troubleshooting before lubing up the parts canon.

Tore into everything yesterday, I have 12v at the fan. I tested the resistor and it seems fine.... from what I can tell the fan is bad.

Queue the drama, because no one in town had the right fan. Mine has a 2 spade connector, every fan at ever parts store had a one blade connector. It's always something. I dawdled so it's no one's fault but my own, I wanted to get it buttoned up and ready for a trip at the end of August, before I leave for a 2 week work trip here. Oh well, ordered my parts, I'll fix it when I get home. Hopefully...

 

[east302]

If it’s the ground spade that’s missing, some aftermarket fans don’t include it. You’re to transfer your old one to the new one.