Vinnie, Did you ever find out what the problem is (was)? I am having pretty much the same issue on an 87 Celica, it also has the cableless control unit. I have had the radiator flushed twice within a week to see if it was a clogged heater core. No change, I disconnected the wire that controls the heater core bypass valve so it is always open. I never could find the blend door so that remains an issue but I am curious about what you found out with the electronic control assy. Did it solve you problem initially?? Have you changed any of the heater solenoids? Thx, Roy
"vinnie" wrote: > I am on my second control unit in 2 years. The fan works > fine, but > the heat turns on and off at its own will. I forced the > water valve > open, but that doesn't fix it as I believe there is an air > flap that > would need to be forced open. Does anyone know where I could > find a > wiring diagram or know of a repair for this. Searching > through > threads this seems to be a common problem. Thanks! > > Vince > Calgary Alberta Canada