Please help ! what is the common denominator?

I got a problem now 2010 international ProStar eagle. First off the mechanic shop that left the hood open and the windows down for two months allowing water to flow through is no longer in business they have been taken to court have filed bankruptcy, so there is no making them fix it.
I have cleaned all the battery grounds even the grounds to the chassis and to the firewall of the cab. We changed the body control module out to a new one we had it flashed one that didn't work we had it re-flashed and reevaluated however the computer does not show any faults in the system it sees the wipers ( turn selector lever )
and Cruise control not responding. ( Controls on steering wheel other functions on the steering wheel controls work )
I think the problem is in the fuse box. I have replaced all of the relays and all of the fuses once again done this several times in the past.
I do not have cruise control, and I cannot activate engine breaks, and AC compressor clutch won’t spin as well as windshield wipers won’t actually no power to the AC system, I used the alternator to fill it so I know the clutch is working. I also have the transmission temperature gauge reading zero and it's got a yellow light on it.
The truck was left at the mechanic with the Hood open and the windows open for a couple of months until I found out.
So this all has to be a common issue or a common situation linked together??
I think what I need to know is how do I remove the terminals from the fuse box the relay for the wiper high and low I think is the same relay for the rest maybe but I think the fuse box may be the issue so is there a way to rewire or how do I get the terminals out of the fuse box so that I can squeeze them tighter?
What say you?
Or how about a wire diagram for these issues from the turn selector lever to the relay to the wiper motor.
From the smart wheel controls ( it has two controllers on the right and left of the steering wheel) to the relay How do I trace all this down?
(I’ve got some of the schematics I just don’t understand them really) What is the comment denominator in everything?

 

Yea I found a fuse terminal that broke off when trying to check the fuses five amp fuse for body control module. I just don’t know if that is going to work with the problems.
There is power to the body control module on the red plug with number 16 pin none without that fuse
I will double check the clutch in the brake action.
Yes I know it will be difficult without the computer hook up but it also has been difficult with the computer hook up and I don’t have time or money to go spend at the stealerships
I just have to keep trying to find a common denominator and trial and error.
Thanks for that I am just looking for paths to take