I have a 2004 2500HD and air is blowing hot even with the AC on and the blower still blows even in the off position? Please help... I replaced the blower motor last month, but speed 5(full power) wasn't working at the time. It works on speed 5 now but doesn't turn off. The problem is on and off though... sometimes it does it but other times it doesn't (just with speed 5 not working). I checked all the fuses and there all good. I think i'm going to try replacing the blower resister and see if that works... Any thoughts?

 

I'm thinking the control head, might try checking to make sure the selector switch is working correctly...

 

The blower resister should fix the problem with speed #5. Blowing hot withy the switch set to cold is probably the blend door actuator. This is a fairly common problem.