Please Help diagnose Climate control problems on 05 Sierra Crew-Cab
 

I'm so happy I found this forum! Hope someone can help! My problem is my 2005 GMC Sierra Crew Cab SLE. The dual climate control is acting strange. In the past year or so it would randomly start blowing hot air while the AC was set to cool. I would stop the truck, turn it off, remove key and open the door then restart. That seemed to clear it up til the next time which would be a month or so later. Unfortunately, it is now stuck on HOT on the drivers side and pass side works fine. I can change the temp on the passenger side. The rear vents must be tied into the drivers controls as they also only blow HOT. I did just replace the original battery the day before this started happening. Coincidence? I read somewhere to remove the HVAC fuse and that would reset the system but no luck there. What should I try next? Or, will this require a trip to the dealer? Thanks for any input you may have.

Sounds like a dealer issue. My brother's old Tundra had a similar problem and it was way beyond his technical skills.

Try this actuator recalibration procedure.
With the ignition switch in the on position, remove the HVAC/ECAS fuse for a minimum of 10 seconds. This fuse is located in the under hood fuse/relay box.
Re-install the HVAC/ECAS fuse.
Start the vehicle.
Wait 40 seconds for the HVAC control module to self-calibrate

Try this..... it SHOULD work
This is a common problem after the battery has been disconnected.

I tried the actuator recalibration procedure exactly as stated above ghostpopi, twice. No luck. :( Should I disconnect the battery?

no disconnecting the battery is why it's doing it start with.

have u tried the key on 3sec key off then on 3sec off then start it, let ac blow on hi for 10 to 15mins. if that don't work with key on (not running) pull the ac relay under hood wait 10secs an put back in.

Thanks ghostpopi!!!!

At the same problem (2003 GMC Sierra - AC/Heater blowing air randomly in different vents) and tried your solution. Worked perfectly the first time!

A big thanks again.

Pierre

Hi Pierre
Welcome to truck forums.

Need help
 

I have a 2005 GMC Sierra SLT Crewcab and on my dual climate control when I spin the control knob the Digital readout jumps up and down. Plus the only way the air conditioner runs cold is when it set on 60° the only way for the heat to work is if it's set on 90°. What do you think the problem is?

I have the same problem.
Did you get it figured out?

Help
 

We are having the same issue, blows ice cubes most of the time then randomly starts blowing warm/humid air