'96 Exploder HVAC

summat doesn't make sense. How does the diverter get affected by the potentiometer? Is there an electrical connection between the pot and the diverter valve, or is there supposed to be variable vacuum applied to the diverter by the control head? Direction of additional troubleshooting would depend on the answer to that question, and I can't tell from the vacuum diagram.

nate

The valve is working properly. Vacuum is applied when the heater control knob is turned to MAX A/C and OFF. Otherwise the valve is held open by a spring and coolant flows through the heater core.

Temperature is controlled by the temperature control knob, what you are calling the potentiometer, which is connected to the blend door motor. The blend door motor is electrical. The position of the blend door determines how much air flows through the heater core, vs how much air flows over the A/C evaporator coil.

Ah! I've let myself be led astray by what I thought I knew... again.

Thinking about it now, I don't know how I suspected variable vacuum would be applied and maintained to control the coolant flowing through the core.

A little more research suggests 15 years was better than many people get from these blend doors/motors.

Just for anyone else who may come across this with the same issue/s, I made a temporary solution last summer by figuring a couple wire ties to hold the valve closed. It took 2, 1 for the valve and 1 to hold that tie in place.

Thanks a million! -----

- gpsman