yukon xl2500 blower motor or board issue?

[saleensonoma]

I have a 00 xl2500 and when I turn the fan on whether full or low it does not work at all but there is a faint heart beat sound coming from underneath. would this be blower motor shot or resistor board issue? I'm also confused on blower to buy from Rock auto. I have auto control setting and obvious rear control.

Thx for any help or suggestions but I need quick help bc I'm on the road a lot and my wife needs it for kids and its cold in Ohio lol. I did search and scan thru interior section

 

[M1Gunner]

Well these things are a lil tricky to diagnose when not physically there to check with a meter, or my preferred method, with a power probe. Typically what happens is the blower motor resistor fails and it's either got no speed or high speed but you say you have a "faint heartbeat" type noise which is intriguing. That sound may be blower motor seized with a partial give or it may be something completely unrelated like an actuator slowly clicking. Again, it's hard to say when you're not there.

That being said, when a resistor fails, and you're stuck with high or no speed, you'll want to replace the risistor AND the blower motor because something caused that resistor to burn up and most likely it's the blower motor going out and pulling more amperage.

You can disconnect the blower motor and supply it power (12v) and a ground to observe its operation if any. If none, then replace the blower motor. If operational replace the resistor and go ahead and replace the blower motor too.

If you're savvy with schematics and have a meter you can pull the resistor and check to make sure you still have continuity between pins.