[quote="Billwill"]Yeah I was also wondering what this "interrupter" light was all about....thought it had something to do with the GF turning on the cabin lights to adjust her makeup while I was trying to get some diagnostics going!

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Very good!
The GDE mod computer went back in finally this weekend at Frank's in Greensboro, NC. We tried to check the NPS by moving the gear selector to R and checking the back up lights, and they were on...according to another Jeep mechanic, Gentry, here in GSO, if the neutral switch is foul then the lights will not come on.
Frank, got power to the starter and it would turn over, but not start....I am thinking ok, that means the starter is working and that's about it. He was thinking that all diesels should start if turning over...my thinking is that this has limited value.
I am towing it to another mechanic, Gentry, in Greensboro tomorrow, to let them have a shot.
The service manual takes you right through most of the checks, which I supplied to Frank, but I think they were still using the subjective method of hunt and peck to see what was wrong.
Sad to have lost 3 weeks while they messed around with the Lib, but there you go, even nice guys can mess up too.
Glad to say I got with you guys on this, and the GDE Eco Tune...just cannot wait for my first trip to MS, 800 miles one way from here...to play with and report MPG, vs steady MPH cruising.
Cheers!
Jim