A different AC question

tsargentjr

I have a 2005 Yukon XL.  In the last year it has done this thing that drives me crazy.  The AC display will just turn off or an "L" will appear where the numbers show up.   The AC/heat will continue to blow hot or cold (stays however it was when it went out) but you will bo longer be able to control it or turn it off (i.e., nothing working on AC unit).  Then after a while (few minutes to 20 minutes) it may come back "on" and I'll be able to control it.   

I have brought it to GM dealer and they have "fixed" it twice but obviously have absolutely no idea what it is.   They actually told me that when it happens to disconnect the battery and reconnect it.  What?

Turning the vehicle off and restarting doesn't work.  Cussing at it doesn't work.

Any ideas?  Thanks in advance, Tom

thecardoc3

Can someone pull codes from all of the modules on the car and then you post them? The factory tool preferred, GM Tech II or at least a full professional level scan tool. We need to specifically see if any UXXX codes are setting, and from there what codes can be retrieved from the HVAC control head.

The codes generated and what modules they are found in will help narrow the focus.