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hard to believe a single instance of parking a great car outside one nasty weather night would be an issue, but lets see if we can help...
it starts and runs, but have you gotten it up to full operating temp? moisture that's obviously inside the vehicle may have collected on the electronics and shorting things out.
I'd first find the fuse indicator labels and verify which fuse handles the instrument cluster. then remove those fuses. then I'd start the car, and try driving around and see if the transmission shifts where it should, then go for a short drive and let the car get up to operating temp. next I'd get the heat and defrost set to max, and get the inside of the car as hot as possible. once I'm sure it's fully above freezing inside the car, and out, I'd put in new fuses for the cluster, and see if it works.

oh. and dry up the water you find. pull up the floormats etc...

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John HAUL AWAY, OR CRUSHED CARS!!! HELP ME keep the cars out of the crusher! A/C Thread
"as I ride with my a/c on... I have fond memories of sweaty oily saturdays and spewing R12 into the air. THANKS for all you do!

My drivers:
1987 190D 2.5Turbo
1987 560SL convertible
1987 190D 2.5-5SPEED!!!

1987 300TD
2005 Dodge Sprinter 2500 158"WB
1994GMC 2500 6.5Turbo truck... I had to put the ladder somewhere!