Temp control

[Tkkracing]

Hello, I have searched but can't seem to find any posts on this. My truck only blows hot air. The cool heat knob has no effect and neither does the knob that changes air location. The fan blower switch works perfect. Also the a/c button does not work nor does the defrost button and their light don't come either. I have replaced my ignition switch as well as the temp control panel. I can't keep tossing parts at it so I'm in need of some help!!! Thank you in advance!

 

[HolyRamBatman]

Hey TK welcome to RF.

What year is your truck? Have you checked the fuses?

 

[Tkkracing]

It's a 2002 1500. I have checked all the fuses and they were good. Thank you

 

[chedched]

This is either a bad control head or two seperate issues. My bet is a bad control unit.

 

[Tkkracing]

Is the control head the piece with the heater controls? If so I replaced that.

 

[chedched]

Yes. Was it a new unit or used? Have you checked for trouble codes? They are very strange issues which I'd assume can be attributed to the control head or the module which controls it. I'm pretty sure the hvac system is controlled by a TIPM in your trick.

 

[Tkkracing]

Ok I figured out what the problem was. There was a wire on the bottom of the fuse box that was broken in the white plug!!! Fixed all issues. To diagnos problem check for 12v on fuses 35 and 36 if no voltage look for black with red wire in the white plug that plugs into bottom of fuse box. Hope this helps someone else