2004 Silverado Dual Climate Control Problems

[Danny Tanner]

On my way home today my A/C, which normally turns my truck into a meat locker, all of a sudden started blasting hot air, as if I cranked the heat up. I turned the A/C and vents completely off for a minute, then turned them back on and nothing changed.

I know it's not an A/C failure (at least not a complete failure) because the passenger side of my truck is still cranking out nice, cold air. So it's like I've got the driver's side cranked up in the red and the passenger side in the blue. So I moved the control tab up into the warm (it felt like it got even warmer but it could have just been all in my head) and then back into the blue, it changed nothing.

When it happened, I heard nothing snap, pop, clunk, etc, my temp gauge didn't change nor did I feel my engine bog down (or up, I guess). It was just cold air one second and hot air the next, not even a gradual warm up.

I've only been home for a few minutes and I'm going to sit on the couch and cool off for a few minutes before going back out into the hot ass garage to start looking at it. Is there something I should check for? I'm going towards the fuse boxes first, but I'm thinking I've never seen a separate fuse for the driver's side temp control, but then again I've never looked for it, either.

Any help is appreciated, I don't want to drive from my passenger seat like a mailman just to be comfortable.

 

[J.P.]

Just a quick guess.....
You might also look at the duct work.
Maybe the flap (or whatever) that selects hot/cold on one side has gotten stuck or something.

That, or maybe the resistor pack or or a relay is bad

 

[Shoot Summ]

My '05 Sierra was doing the same thing intermittently, before I sold it....

I would suspect the flow control dampner control...

A quick google of "GMC Sierra blows hot one side cold the other side" gets a bunch of hits,

http://www.google.com/search?sourceid=chrome&ie=UTF-8&q=gmc+sierra+blow+hot+one+side+cold+the+other

one referred to this thread...

http://www.truckforum.org/forums/gmc-truck-forum/6083-heat-wont-shut-off-and-is-too-hot.html

 

[J.P.]

My '05 Sierra was doing the same thing intermittently, before I sold it....

I would suspect the flow control dampner control...

Yeah...that's what I meant.

 

[Shoot Summ]

Yeah...that's what I meant.

I was wrong, they are actually called "blend door actuators".

 

[J.P.]

Yeah.....that too.

 

[PUMPKIN]

my 03 gmc did the same thing. it is the blend door actuator. i think there are 3 of them, luckily the one you need is the easiest to get to. it just above the transmission hump under the large black cover that covers the blower motor and underdash stuff you can get it off by removing 4 screws. When you change this item make sure you adjust your temp knobs to the middle exactly or you will break the new actuator. you can find the actuator on ROCKAUTO.COM is the chaepest i found it.

Thats is how i fixed mine anyway. also if i shut my truck off and started it back up sometimes it would go to working correctly again.

 

[Mechanicalmehem]

either the blend door actuator for the driver's side or the control head(less likely)....lemme see what I can find on info..

 

[Mechanicalmehem]

2004 Chevrolet Chevy C Silverado - 2WD |

Temperature Valve Actuator Replacement
Removal Procedure
•Remove the IP insulator. Refer to Instrument Panel Insulator Replacementin Instrument Panel, Gauge., and Console.
Disconnect the electrical connector (8) from the air temperature actuator (9).
•Remove the air temperature actuator retaining screws.
•Remove the air temperature actuator.
assembly is backwards..gm warranty pays 4 tenths for this so less than half an hour you should be done...these are gm instructions..paraphrased....
--Mech

 

[Danny Tanner]

Wow, thanks a lot guys! I haven't had a chance to look yet, but will later on when it cools off. It's just too hot to be fiddling around in the heat and I haven't had enough beer yet to brave the elements.