Andy,
I think you have the correct EPC diagram. Do you have service manual article 83-020? It shows how they are wired and it looks like the pins on those switchover valves are polarity dependent. The two diagrams also show what power interruption (heat levers down - microswitches open) does to those valves and what power application (heat levers up - microswitches closed) does. From memory, there is a locator on the electrical receiver that insures 12V goes to the correct pin.
If you have that bench test set up correctly and can't get the solenoid to switch ports, I think you may have to replace them. I pulled some salvage ones and will dig them out when I get home. Functionally, I can't see the difference in those valves; no idea why 2 part numbers.
I think you have the correct EPC diagram. Do you have service manual article 83-020? It shows how they are wired and it looks like the pins on those switchover valves are polarity dependent. The two diagrams also show what power interruption (heat levers down - microswitches open) does to those valves and what power application (heat levers up - microswitches closed) does. From memory, there is a locator on the electrical receiver that insures 12V goes to the correct pin.
If you have that bench test set up correctly and can't get the solenoid to switch ports, I think you may have to replace them. I pulled some salvage ones and will dig them out when I get home. Functionally, I can't see the difference in those valves; no idea why 2 part numbers.
