GCSS

I have a 1995 Cummins engine I just bought and the microswitch on the throttle has three wires... can anyone tell me how to wire it? I picked up a vacuum solenoid which I can get operational, but just not sure about the throttle switch wiring... any help appreciated.
Thanks.
DD

infidel

I would think the Jacobs is the same as a Pac
http://pacbrake.com/PDF/L2014.PDF

GCSS

nope....Jake has three wires on the throttle switch

pind

Are you saying that the wiring harness has three wires, or jsut three poles on the micro-switch

infidel

If the switch is using three wires it must mean vacuum is used to open the butterfly as well as close it.
Pac only uses two wires because a spring opens the butterfly.
Vacuum only closes the butterfly.
Pac's solenoid vents the vacuum to let the spring shut the butterfly, sounds like the Jacobs must use vacuum to hold the butterfly open.

GCSS

yes that is correct. Jake has only one nipple for vacum. I saw the diagram for the pac and noticed the three nipples on the Vac solenoid. I wondered if the "third one was basically plugged or functioned.
I would rather have it the Jacobs way...if there was a loss of vacum, the butterfly would remain open and not hurt the motor.

GCSS

the Jacobs-supplied micro switch has three wires... Im going by memory but I think it was a black,a green, and a white one

infidel

That's the way the Pac works too.
A spring holds the butterfly open, no power or vacuum needed.