HVAC Issue

[Simzie]

Good afternoon, I have a 2013 K 1500 LTZ, and I'm experiencing a problem with my hvac system. Its a electronic dual zone system, mode door and temperature servos are non responsive either by the control head and my 2 way scanner. My gut is telling me the control head is bad.. I have replaced the mode door servo and the drivers side temp servo with known good replacements and attempted to calibrate numerous times. The only thing that has changed is the temperature coming out of the vents because I have changed position of the blend doors when I replaced the servos. I haven't checked for voltage at the servos, I know its all low voltage 0-5 volts that I will be looking at but I really don't feel the test is necessary. I checked live data and the counts never changed when I changed mode of temperatures. Something strange I did find out about the control head is it has a production date of 2002..I suspect the p.o. may have had issues with it in the past.
Anyone have suggestions on way I should do next. Is it the control head or is there another controller involved with this system?

 

[zora]

That's a pretty old head to have in a 2013. Unless you can find the factory diagnostic steps to see what they call out, see if you can find a newer head.

 

[Simzie]

That's a pretty old head to have in a 2013. Unless you can find the factory diagnostic steps to see what they call out, see if you can find a newer head.

Thanks for the reply, As much as I hate just replacing parts without proof the part has failed, I went ahead and ordered a new head for it. Crossing my fingers this resolves my issue. What also seems odd is part replacement from many sources show a , what I would call a analog, replacement that has two knobs rather than the digital display with up/down buttons.. ? BTW, The replacement I ordered is a Delco # 15-74262