Chassis Electrical Problem on 2002 Newmar Mountain Aire Diesel Pusher

[LibertyCall]

In November 2015 I bought what appeared to be a well-taken-care-of 2002 Newmar Mountain Aire diesel pusher with 115K miles. After a new set of tires and full maintenance, we immediately left the New Orleans area and drove to Orlando through a non-stop rain storm with no issues. Have since taken several other 12-hour trips with no issues. Then in August of 2016, after having the dash AC repaired, the dash lights and gauges started acting up. The oil, battery and coolant lights were first to act up. Lights on - gauges off. They would cycle through over and over. The problem progressed to additional lights coming on and going off. Then the transmission started to act up just a bit by upshifting going uphill and downshifting going downhill. Then it went into limp mode and wouldn't go beyond 4th gear.

Numerous helpful and customer-oriented calls to Freightliner Custom Chassis helped the local Empire Truck repair. So it went into service in early September. It's still in service and I've run up over $6K in troubleshooting costs. They've replaced the VDC - Vehicle Data Controller, the ECM - Engine Control Module and the dash Light Bar. The problem remains, just not as bad. It's worse when it's raining. Every engine space connector has been checked for water and corrosion with no evidence of such. Now they want to take the dash out (found out the previous owner had it in for "sizzling sound" coming from the dash but didn't disclose that). This will be a minimum of another $3K of work - and no guarantee of identifying the problem.

Any Newmar owners out there experience anything like this?

[gemert]

I' not an expert but I do not believe in coincidences! This all happened after you had the dash AC repaired. I would be looking for loose connections or broken wires, even breaks inside connectors or wire crimp connectors in the areas that they worked on while repairing the dash AC. Just a thought.
Good luck.