Chrysler Repair: 92 Lebaron Instrument cluster

Question
Hello; I have a 1993 Chrysler Lebaron convertible. Before I bought it, the car had sat for a year without being driven much, and, is originally a Florida car so it has some heat damage to the top / trim, etc., (as in, it sat and baked a little). Due to this, I'm sure there are compartment leaks. Not sure if this is pertinent.

The dash (and most everything on it), and the electric door locks, have had intermittent outages, which now seem to be permanent. Previously, when it rained, or was cold (winter), there were no dash lights, any instruments in the cluster besides speedometer, intermittent wiper(although the low / high settings worked) or door locks. Then, they would suddenly just come back on. However, the tachometer has never worked, regardless, although the speedometer does, also regardless (never goes out).

My fiance has checked fuses he has access to, and none seem blown. At one point, the wipers would come on and not shut off, even if the switch was off, so I had to pull the fuse periodically to get them to stop running while driving in dry conditions. I have been told there is a wiring harness somewhere on the passenger side of the engine compartment that has been a classic issue with this car, but, to be honest, I'm not great at any electrical issues with vehicles.

Can you point me in the direction of what and where to look for this issue? Thank you so much!

Answer
Hi Caprice,
Let us start with the instrument panel functions. Check fuse #14 (5 amp) in the fuse box under the dash. Then check at the lower front corner opening in the body where the passenger door is located (this is called the cowl area) where you should find a black/orange ground wire that is held in place by a screw to the body panel at the lower front door opening. Make sure the screw and islet for the wire are shiny and tightly connected to the body. If both of those are o.k. then the instrument cluster itself needs to be removed and the connections of the fuse and the ground wire to the circuit board of the cluster need to be verified as  being connected. Do you have a volt-ohm meter to work with?
Then we can focus on the wipers.
Please read the PS (below) and respond to it.
Thanks,
Roland