Any one that can tell me the location of the Heater Valve Solenoid on a 1987 300 sdl. My wife is going on a road trip and thinks she wants the AC working. I am not sure that this is the problem but I have heard that it is the likely suspect. AC blows sort of cool sometimes and somtimes it fades to warm. Ac is fully charged and clutch works. Also I can't seem to get the center ducts to blow at all. I don't have my shop manual yet and she is leaving tomorrow.