Alrigthty, this is what i got. My heater isn't working. I changed my digital heater control unit on my 92 GXE. I can vary it from 65-85 degrees. Here's the problem, The vacuum @ the back of the fire wall is engaged all the time no matter what. (it closes off the water from flowing to the heater coil). I unplugg one of the vaccum lines and the valve disengages and the heated works fine. I checked the voltage on plugg going there and there is 14VDC with the heated on and when i turn the heated of there is 12VDC there and the valve never disengages. Put another valve assy. on and the same results. Are there any other relays that controls that valve assy or is it the computer!!!!!!!!!!!!!!!!! help