Heater/ac Contol Head Problems

[hed0014]

I have been having trouble with the heater/ac control on my 1991 Chevy Silverado for a few years now. They just go "dead", no light, no LCD, no function. Remedy until now is just to replace the control head. Last one I replace lasted over a year. Now with a new one it will not power up; not lights, No LCD, no function. Seems like it is not getting any power .

 

Fuse in dash cluster is OK.

 

When other control head powered up there was no problem with functions.

 

Any help?

 

John