01 c1500 Heat / AC

lakenut · November 20, 2006

Hi,

First post here.

Have 60k miles on my truck. When I turn the temp to high something sticks and won't allow a cooler temp to be selected. I can turn from hot to full cold and the air temp from the vent doesn't change. When I shut the truck down for a few min. the problem goes a way for awhile only to return when things get really warm inside.

Any ideas as to what is causing this? Fixability? I am fairly handy. Is this something a mechanic must work on or is it a DIYS project?

Thanks in advance!

Black Bart · November 22, 2006

A friend has a 2000 Tahoe that had the same problem and we did the fix discribed

above and he has not had any further troubles with it . we noticed that one of the gears did not move freely on the shaft, after reaming the gear out it turned easier

on the shaft.

GM-Tech · November 22, 2006

A friend has a 2000 Tahoe that had the same problem and we did the fix discribed
above and he has not had any further troubles with it . we noticed that one of the gears did not move freely on the shaft, after reaming the gear out it turned easier

on the shaft.

<{POST_SNAPBACK}>

I don't doubt you one bit. I'm just saying to be careful removing the gears. We don't waste our time trying backyard fixes on these things. If a component is not working correctly, it just gets replaced.

GM-Tech · November 20, 2006

Probably one of the a/c actuators. Would need a little diagnosis with a scanner to see what/which it may be. Actuators are our biggest problem. Never seen a door stick and a bad a/c control head is fairly uncommon.

Can you fix it yourself? Probably, but only if you know which part is the problem.

lakenut · November 20, 2006

How many acctuators are there? Are they expensive and could they all be replaced?

And by scannner are we talking ECM scanner?

GM-Tech · November 20, 2006

How many acctuators are there? Are they expensive and could they all be replaced?

And by scannner are we talking ECM scanner?

<{POST_SNAPBACK}>

There are four that I can think of off-hand. Sure, they could all be replaced, though a couple are a royal pain and not something you want to replace if you don't have to... You gotta pull the dash. I don't do parts and don't know prices.

I'm talking about a scanner that is capable of reading HVAC (a/c) data. The cheapie ones you can buy will only scan the engine control computer (ECM). Autozone will only show ECM data. A fully functional scanner like we use at work will cost several thousand dollars.

lakenut · November 20, 2006

Where are the "easy" ones located at?

GM-Tech · November 20, 2006

Where are the "easy" ones located at?

<{POST_SNAPBACK}>

The left temp actuator is on the bottom of the case, right out in the open.

Black Bart · November 21, 2006

You can possibly repair the actuator module quicker than it takes going to

the dealer to buy a new one, it is the one over the hump on the bottom

of the plenum. carefully take it apart and you will find that at least one of

the little gears is binding on the shaft, take a drill bit just a little bigger than

the shaft and turn the bit with your fingers enough so that the gear does not

bind when on the shaft.

Reassemble and your problems are over.

GM-Tech · November 21, 2006

Never heard of binding gears being a problem in these, but hey, if this fix works for you I say go for.

Be advised that all but one of the gears are in a specific position. If you just go pulling the gears out and pay no attention, you'll probably put it back together and be in worse shape than before. Even being off one tooth can be a problem. Only one of the gears is an idler gear whose position doesn't matter, but the others do.