Climate control for A/C

[dalebig]

Have a 2004 Duramax 3500 6.6L with dual climate control. Sometimes when the a/c is on, the driver's side will start blowing hot air, while the passenger side will still blow cold.
When I shut engine off and restart, both blow cold air again. This doesn't happen a lot.
What would be the remedy for this?

Thank You,
Dale

[Duramaster]

You might possibly need a calibration update for the HVAC control head. Take the vehicle to a dealer and have them check the HVAC for any DTC's.

[ccurran]

Did you replace your batteries recently? I replaced mine and it resets the AC controller. I reset my controller as such:

1) Start truck
2) A/C comes out defrost - wait about 10 to 15 secs
3) A/C then starts coming out the floor vents for about 5 seconds
4) A/C then starts coming out the dash vents.
5) While the A/C is coming out the dash vents, turn A/C OFF (otherwise it cycles back to defrost for good).
6) Turn truck OFF

Restart truck, A/C will work fine. This has been tested multiple times on my truck (05 2500 dmax) and a few others with similar A/C problems (hot on drivers side, cold on passenger).