I'm no mechanic, but I have a little experience with vintage stereo electronics, and just this week revived a 4 way flasher relay on the '97 Saab 9000...( re-flowed the solder pads on a relay printed circuit board, cleaned relay contacts...)

The wife complained Saturday of electrical gremlins attacking her '05 Pacifica. Suddenly would see no speedometer, or tach.
codes: U0155, U0140, P0138.

The Sonny took it that night and suffered a will not start. Battery dead.I wasn't around so the car was towed to a indy mechcanic.
They replaced the battery ( original.....!)
Still had the speedo and tach come on and off, , etc. They said have to go to the dealership, we've no clue.

Joined and checked on here. Then did 2 things...switched the keys ( mine, never used for hers), and crawled under the front drivers side bumper WHERE THEY PUT THE PCM CONTROLLER !) in front of the front wheel....re-connected all the connectors. Took neg battery terminal off for 15 minutes.
re-secured, and drove. Problem gone.
https://www.chryslerforum.com/forum/...bilizer-15850/

Thank you people who have posted these things before.
Saved me a expensive trip to the Stealership.

PCM controller in the front bumper ? Like a human evolving with his brain in the foot. We would never be writing this if we'd been engineered that way !

 

If the problem comes back, check the grounds on the drivers side below the battery area. There are 2 or 3 of them there attached to the body that often go bad. It's very possible that you moved those wires enough messing with the harness to make those grounds make contact. Those grounds can cause all kinds of problems with the instrument panel, horns, wipers, pwr windows etc.