i have 1992 dodge truck- d-150, the heater/ac/vent control went out, i have no blower motor and no a/c, i checked the fuses, my buddy sd he has a dodge dakota do the same thing, it was the black box looking thing on the fire wall that is the main ground to the control panel, it broke in half, he had to solder it up and works fine, i cannot find this box on my 92'dodge truck, but we think this is the problem, because when you push the button to turn on any of the buttons on the control panel, the brake light in the dash comes on and stays on till you turn off the button that you pushed in, can anybody help me with this, it is getting pretty hot driving in mid day and i know it is something very simple, the a/c blow cold when i can turn it on before.
thanks

please help

Brake light in the dash coming on? This sounds serious.

Try the truck section.

I just fired up my 93 W250 the other day for the first time in ages and it's doing the same thing. Can't help with the solution but I have the same issue. Select any heat or a/c button and the brake warning lamp comes on, also no apparent functionality of the heater or a/c. At least I don't need mine right away, it hadn't run for a month.
Mike

i think it is a ground, but i do not know where to start