2001 Yukon Front Blower Does Not Work Sometimes

Starrman · May 25, 2012

I searched and read older posts about this problem and read about the wire harness over heating and melting and making only partial/intermittent contact and also that GM extended the HVAC warranty to 10 years and 120k miles. Well I'm only at 119k miles but the vehicle is an '01.

I have manual HVAC controls by the way...

I replaced the blower resitor pack last year because I was only getting speeds 4 and 5. That fixed that problem. Just recently the blower would stop working on all speeds. Sometimes it works fine, but then shut off vehicle and run into store and come back out and then it won't work. Drive for a while, like 10-15 minutes then it comes on. The rear works fine.

I thought it might be the resitor pack/relay sticking or maybe the wire harnes melting and pulled the panel off and checked the wire harnesses and all looked fine. When I was down there I started vehicle and blower was not working and I tapped on the relay part of the resitor pack and the blower kicked on so I figured it was a bad resistor pack. I exchanged it for a new one under warranty and blower worked fine for the first 2 days, then all of a sudden back to working intermittently.

Could the blower motor have a short in it causing this problem?

Is there anything else besides the actual blower speed contol knob on the dash that sends a voltage signal to the resistor pack/blower motor that could be sticking/going bad?

gmtech4 · May 25, 2012

the cost of the HVAC control head is to much to guess,,it is a module and has data thru scanners,the blower motor is a thought but in the end it needs to gone thru by a tech .....you could have a terminal retension issue so throwing parts at it MAY bite you in the buttt

tread carfully bud

my 2c

Starrman · May 25, 2012

So the manual HVAC control unit with the 3 knobs is that complicated?

asc08 · May 25, 2012

The warranty extension for the resistor pack included replacing both the resistor pack, and the wiring connection to it. You may want to replace that as well, because it sounds like there may be a connection issue if it runs after you tap on it (I think that is what Rob was referring to when he mentioned the terminal retention issue).

Also, if tapping on the blower makes it work, it is most likely an issue in the area of the blower. If you tapped on the control head and that made it run, I would look more closely at the control head.

From an electronics perspective, the controller is not very complicated, but relatively expensive compared to resistors and wiring connections. If you are using the trial and error method (or throwing parts at it, as some like to call it), you need to start cheap and work your way up in cost until you get to your personally set dollar threshold before you take it in and have it scanned with the proper equipment.

Starrman · May 25, 2012

I haven't spent any money on it yet. The resistor pack I had was still under warranty from when I put it in last year because the stock one was fried. I got the replacement at no charge, but apparently that was not the problem. I figured it or the wiring was the problem seeing that when the blower wasn't working I could tap on the bottom of resistor pack and the blower came on. All the wiring and connectors looked fine. Figured there couldn't be too many different parts that could be causing this problem and that they wouldn't cost more than a diagnostic trip to the dealer...lol

How much does the dealer (or a shop) charge for an assesment or labor nowdays? It's been very, very long time since I took any of my vehicles in to a shop for work. I do just about everything myself...lol

asc08 · May 25, 2012

Most likely $75 to $100 for a diagnostic test. If the controller is bad, that will probably show up on a computer check. The wiring connector may not. I believe there have been a few others out there who replaced the resistor pack and had the problem persist until they replaced the connector as well.

Your best bet will be to go to the dealer who has the equipment to check more than just the engine computer.

gmtech4 · May 26, 2012

Most likely $75 to $100 for a diagnostic test. If the controller is bad, that will probably show up on a computer check. The wiring connector may not. I believe there have been a few others out there who replaced the resistor pack and had the problem persist until they replaced the connector as well.

Your best bet will be to go to the dealer who has the equipment to check more than just the engine computer.

you are on the money bud !!!! everything you said is perfect ,and your previous post here to !!!,,i want the op to look at the connector to the resistor ,,,,,any discolouring means heat of the connector/terminals ,,carfullt look for that replace if nessesary,,,,GMs connector has all white wires on it ....i know... anyways ,just do 1 wire at a time and stagger the butt connectors so you dont end up with a wad of butt connectors to tape up ...

have a good week end guys !!!

Starrman · May 26, 2012

I'll probably take it to a dealership and have it checked out sometime then. Of all the running around I did today it only didn't come on when I started the vehicle twice, but then came on a few minutes later. The rear blower still works fine and I have a couple of the adjustable ceiling vents over the back seat kind of pointing towards the front so it's not too bad when it doesn't come on.

I checked over the wire harness when I replaced the resistor pack and cabin air filters a couple days ago. It looked fine, no signs of over heating. Had a black connector plug and different colored wires on it and wrapped in thin electrical tape. A couple of the wires in the harness looked to be a pretty heavy gauge, heavier than the others. Maybe it's been replaced already. I've owned it since '07 and bought it from my father in law who bought it new in '01.