OH4CHEV

Hello, i have a 2004 ccsb 2wd, 5.3, auto lt. When driving down the road, my air turns over to the hot side sometimes, but I dont touch the climate control, it has the dual climate control with digital readout/ twist to set temp. I live in houston, so this was real pleasant. I put the truck in neutral, turned the key off and back on, then turned it to defrost full hot, then twisted both sides back down to 60^. It worked all the way home yesterday, then part of the way to work this morning it did the same thing. Is there a vacuum block or relay or valve somewhere that controls the heater doors in these trucks? Or does anyone else know what is going on, i am sure that I am not the first with this problem. Will the scanner software from HP tuners diagnose this problem?

Also, has anyone ever had a heated seat go bad, first the drivers side quit, then the passenger side quit. Seems like this truck has a lot of Gremlins or something.

thanks for the help in advance.

icetraxx01

From what I have been reading it might be the a/c controller. I have a buddy that has the same problem on his 05 that started up recently. His goes from blowing cold to hot and only starts blowing cold once he turns the truck off and back on.

KySilverado

iTrader: (7)

The ventilation door are moved by stepper motors. No vacuum or cables.

HP Tuners, AFAIK will not scan the A/C controller, so no it won't diagnose.

I'd look at replacing the climate control module. I bought one a while back just in case, still have it if you are interested.

I had problems with mine after replacing an A/C compressor. Unhooking the battery for about 5 minutes cured the issues I had.

OH4CHEV

dont mind the caps, i work in all caps at work.... sorry...Ky, i think your post came in as i was typing this one, I was replying to icetraxx01 when I started typing in caps, damn work programs....
Monument Chevy wants around 90 bucks just to diagnose it. The guy there was saying that it could be the dash controls or the door actuators, he says there are six, but it is going full hot on both sides (zones), so i would assume that if it is an actuator, then it would be the one that controls the heat only, not a door that controls one of the separate zones.

KySilverado

iTrader: (7)

I edited the above post, may want to re-read.

Yes the climate control module is the the part with the ***** and digital screen.

OH4CHEV

didnt mean to type in caps.

I will try unplugging the battery at lunch if i can find a 5/16 and see what it does.

OH4CHEV

Hello,

I unhooked the battery (pos. and neg.) let it sit for about 3 hours, hooked it back up, then turned on the truck, and cold air, for about 25 seconds, then it switched over to hot.

do you think its the control panel after all? any ideas if not?

thanks.

OH4CHEV

ok, after reading another post, a guy on there said to disconnect the battery, then reconnect after a minute or two, then do not touch anything, so i did that, let the ac control module relearn, and it seems to have fixed it.
What in the heck makes these things go haywire?

KySilverado

iTrader: (7)

I forgot to mention the not touching anything after a battery disconnect, it goes through a re-calibration routine afterward and adjusting things screws it up.

Glad you got it going. I played with mine after a compressor change for several days. The compressor clutch wouldn't engage like it should.

LightFighter

iTrader: (1)

that happens to me from time to time....... seems like a common problem with these trucks