[Leonard Welch]

An update...although by changing the TCS temperature switch the fuse doesn't blow any longer, I still get vacuum advance all the time. To diagnose the sitautiong:

Changed the TCS vacuum solenoid to see it it was broken. No change.

Changed the TCS transmission switch. No change.

Tested the voltage on the TCS temperature switch. No power when cold. Power does come on the blue wire when hot. That blue wire goes over to the TCS vacuum solenoid. Same thing. No power when cold. Power when hot. And I checked the power on the tab of the solenoid itself. So power is making it's way onto the vacuum solenoid.

I also disconnected the TCS transmission switch altogether to see if that was causing a ground all the time (which is what it's supposed to do only in fourth gear) No change.

At this point, I'm wondering if BOTH of my TCS vacuum solenoids are bad since power is making it to them but it's not blocking vacuum to the distributor. The service manual says that when the solenoid is 'energized', the vacuum advance should be blocked.

Is there a way to test and/or fix a broken solenoid?

I'm completely stumped!