Turbo 350 invertor lockup switch???

[wayfastwhitey575]

I have a 1980 C10 with a turbo 350. There is a single wire coming from the drivers side of the transmission that plugs just above the brake booster and from there it goes to a vacuum devise of sorts (not sure what it is called). From what I can find from an online photo search is this locks up the invertor at cruising speeds. Should it be hooked it up to manifold or ported vacuum?

 

[Goldie Driver]

From the factory, it was supplied by a thermal vacuum switch that did not receive vacuum until the engine hit a certain temperature. On Goldie now it is hooked to manifold vacuum without the TVS. My transmission guy did not feel the converter lockup when the transmission was cold would be an issue. He did change a spring so that the converter will not lock until roughly 40MPH, however.

 

[wayfastwhitey575]

Thank you, I believe everything is there including the thermal switch. I just have a hose with a broken plastic fitting in it that looks like it was a T from other vacuum lines. I will T it into the manifold vacuum and see what happens.

 

[Ricko1966]

I don't know the answer,I do know how figure it out though. If your Hobbs switch, is normally open it would be on ported vacuum, no vacuum at Idle switch opens,converter unlocks. If it is normally closed it would need vacuum at Idle to unlock. So if would need manifold vacuum