my mileage dropped to 0. I see that the trip computer is showing all values changing except distance.

Anyone know where the pickup on my 86 5.3 is?

 

The T/C uses the same signal as the speedometer, which, on your '86, comes from the speedometer transducer mounted in/on the transmission, LH side....where a cable would be fitted if you had an older cable driven speedometer.

Does the speedo work OK? If so, the problem can't be the transducer

Cheers
DD

 

yes. Speedo behaves normally. I guess that points to a connection issue between transducer and TC.

Pulling the Comp would be a good place to begin. Hmmmmm...

 

Sometimes just removing and reseating the TC connector works wonders.

But the TC itself might just be suffering old age. IMO it's surprising how long they survive. Automotive 'gizmos' often don't remain fully operational more than a few years. These old Jag TCs are +/- 30 years old.

The TC innards were revised at least once, maybe more, during the mid-late 80s, according to TSBs

Cheers
DD