ac blows hot, then cold - PerformanceTrucks.net Forums



ac blows hot, then cold

Reply
 
Thread Tools Search this Thread
Old 08-12-2010, 09:15 PM   #1
Registered User
Thread Starter
 
Join Date: Aug 2010
Posts: 1
Thanks: 0
Thanked 0 Times in 0 Posts
Default ac blows hot, then cold

I have a '05 GMC Sierra, crew cab, 5.3, auto tranny, with about 150000 miles on it. AC control panel has two round dials, with two hot/cold sliding controls. Out of no where, the ac started blowing hot, really hot air. I pulled over and checked under the hood, the belt is good, the compressor was running, (so i ruled out the low pressure switch). The ac continued to blow hot, alot hotter than the outside air which was at 104 at the time. I checked all the controls and they were set correctly. i turned the ac off and drove for about 15 miles and tried it again, still blowing really hot air. I parked the truck for 2 hours and tried it again... now i have cold ac, just as cold as its always been. I'm on day two with the ac working as it should. Can anyone tell me why the ac blew hot, really hot air? I can only think that maybe the door under the dash that allows the ac cold air into the cab closed and allowed the heated air from the heater into the cab??? Any answers would be appreciated. thanks.
jvaja is offline   Reply With Quote
Old 08-12-2010, 09:41 PM   #2
TECH Apprentice
iTrader: (4)
 
qwank's Avatar
 
Join Date: Aug 2003
Location: Hudson, NH
Posts: 371
Thanks: 0
Thanked 1 Time in 1 Post
Default

theres a software update for the HVAC controls. sometimes when you put it on full hot or full cold, the position sensors in the blend doors will open past the normal range for the sensors to read, it sets a code and defaults to hot.

GM bulletin #06-01-38-003 if you want to look it up
qwank is offline   Reply With Quote
Old 08-25-2010, 09:23 AM   #3
TECH Resident
iTrader: (1)
 
slpsilverado's Avatar
 
Join Date: Jun 2010
Location: Lexington, TN
Posts: 761
Thanks: 0
Thanked 0 Times in 0 Posts
Default

This happened to me this morning! Thank goodness it was only 70 degrees...it has been 90 in the mornings and that crap would have sucked!

I pulled over, turned the engine off, cranked it back up, and it started blowing cold again. Just like a computer...turn it off and it will fix itself!
slpsilverado is offline   Reply With Quote
Old 08-25-2010, 04:33 PM   #4
Fastest D1 Procharged Truck
iTrader: (30)
 
02_Orange_D1SC's Avatar
 
Join Date: Mar 2007
Location: mASSHOLE
Posts: 3,121
Thanks: 0
Thanked 0 Times in 0 Posts
Default

hmm interesting my truck is doin the same thing
02_Orange_D1SC is offline   Reply With Quote
Old 08-25-2010, 05:15 PM   #5
TECH Junkie
iTrader: (31)
 
hirdlej's Avatar
 
Join Date: Dec 2004
Location: Minneapolis, MN
Posts: 3,470
Thanks: 0
Thanked 0 Times in 0 Posts
Default

[youtube]X75mry1LcFg[/youtube]
hirdlej is offline   Reply With Quote
Old 08-25-2010, 05:35 PM   #6
Fastest D1 Procharged Truck
iTrader: (30)
 
02_Orange_D1SC's Avatar
 
Join Date: Mar 2007
Location: mASSHOLE
Posts: 3,121
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Quote:
Originally Posted by hirdlej View Post
[youtube]X75mry1LcFg[/youtube]
yup that pretty much says what my truck is doin lol
02_Orange_D1SC is offline   Reply With Quote
Old 08-25-2010, 05:45 PM   #7
PT's Slowest Truck
iTrader: (19)
 
budhayes3's Avatar
 
Join Date: Apr 2004
Location: Hackensack, NJ
Posts: 17,869
Thanks: 0
Thanked 0 Times in 0 Posts
Default

Could it be a problem with one of the ever common blend door actuators?
budhayes3 is offline   Reply With Quote
Old 09-02-2010, 09:38 PM   #8
12 Second Truck Club
iTrader: (13)
 
Fastcount03's Avatar
 
Join Date: Sep 2008
Location: Duncan, OK
Posts: 801
Thanks: 0
Thanked 0 Times in 0 Posts
Default

This happened a few times in my 03, if turning it off and back on doesn't work. Unhook the battery for 3 mins and that always worked for me. Whenever you can take it in to the dealer for an update on the software.
Fastcount03 is offline   Reply With Quote
Reply

Related Topics
Thread Thread Starter Forum Replies Last Post
Picked up a new Ride... cheyenne383 GMT 800 & Older GM General Discussion 9 11-13-2015 09:24 AM
Whirring noise...normal or an issue? lukn4trbl355 INTERNAL ENGINE MODIFICATIONS 7 10-21-2015 11:19 PM
01 c3 ecsb awd 6.0 turbo turbo6c3 Trucks and SUV Classifieds 1 10-05-2015 06:11 PM
LS1 Fan wiring help!!! broke wire, goes where? Wrecker 426 Tuning, Diagnostics, Electronics, and Wiring 1 09-30-2015 09:39 PM
Sleeper 535 - Twin Turbo with Tune, $60,200 MSRP, executive express for pennies..TX Closer_2001 Cars and Motorcycle Classifieds 2 09-24-2015 09:15 PM


Tags
05, 060138003, 2007, ac, blows, bulletin, bullitens, chevrloet, cold, gm, gmc, heater, hot, silverado, truck

Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Trackbacks are Off
Pingbacks are Off
Refbacks are Off



All times are GMT -5. The time now is 05:29 AM.


 
  • Ask a Question
    Get answers from community experts
What's your question?
Send