HVAC Problem

[Judge Mills]

Trying to find info for my dad and his 2003 2500 GMC.

 

His HVAC will only blow red hot at 90 degrees and ice cold at 87 and below. There is no inbetween.

 

It has the dual zone digitalHVAC control. So far he has replaced the HVAC control and something he described as the middle air door actuator. He has disconnected/reconnected the battery and checked the fuses.

 

I've similar issues on the forums, but not quite like this. What's our next step?

 

Sent from my HTC6535LVW using Tapatalk

[sefiroxx]

Assuming it's manual control, sounds like a high pressure switch is shutting the system down or a variable orifice is shutting down. You can check the pressure switch with a meter.

 

Sent from my XT1053 using Tapatalk

[Judge Mills]

Assuming it's manual control, sounds like a high pressure switch is shutting the system down or a variable orifice is shutting down. You can check the pressure switch with a meter.

 

Sent from my XT1053 using Tapatalk

Looks like I posted in the wrong sub-forum. Oops!

 

Anyway, It's the digital display dual climate control. I'm not sure if that would make a difference...

[Judge Mills]

Update: we couldn't figure it out, so dad took it to the shop. Apparently there is a temperature sensor in the headliner that went bad. All is fixed now.

 

Sent from my HTC6535LVW using Tapatalk

[grampadirt]

Thanks for letting us know of the fix,it may help someone in the future

[efritz]

need a scanner that can pull B codes, the HVAC system has its own diagnostic software