No heat, ac or anything inbetween.
 

So I installed my aftermarket stereo system a couple weeks back. I know what I'm doing there, did everything properly, no cutting of wires or anything like that. Anyway, shortly after, a couple times here and there when the heater was on it would stop like it was turnned off. Would be off a couple seconds then start up again. I used my vehicle today and there is nothing at all now, no heat, ac, vent, nothing. Controls are completely dead. I checked the connections behind the panel and all seems connected properly. Fuses are good to go. I'm not a mechanic and have no idea what to check. Do not remember if it had done this before I went into the dash to install the stereo. Any ideas?
95 Blazer LT

Thanks

RE: No heat, ac or anything inbetween.
 

So the fan does not work... Is that correct? When you change the modes (defrost, panel, floor, etc), do you hear anything happening?

There are two different systems in these trucks. Most of the mode switches are handled via vacuum actuators. The control unit has a vacuum logic to it that feeds engine vacuum to the appropriate actuator(s) for a given mode. The fan is all electrical control.

RE: No heat, ac or anything inbetween.
 

Correct, no fan. No nothing. Hear nothing on the different modes, it's as if the key was turned off.