2001 Stratus gauges fluctuating

A friends 2001 Stratus 2.7 engine, auto trans, the dash gauges fluctuate and A/C is not working. I have not looked at the vechilce yet but they have had the codes read. Codes Are:
1598 A/C pressure sensor voltage high
1684 Battery disconnected in last 50 starts
1687 No message received from mechanical instrument cluster
1695 No message received from body control module
1698 No message received form electronic transmission control module

The car runs and drives fine.

The battery has NOT been disconnect. Thus it makes me think that the battery cables are corrided. (Evidentally the battery is hidden ) or could it be a bad ground somewhere, or could it be possibly related to the instrument cluster having cracked solder connections?? Any advice is greatly appreciated.

You'll have to check all those things. Talk to a dealer and see if they'll help you w/ the codes. Sounds like there are some electrical issue all around. Start w/ the ground and work your way from their

The code about the battery being disconnected will appear anytime a code is stored in the computer. I am not sure why, but everytime I have had a code stored, that code is always there.

I agree with AZeline, it sounds like an electrical issue. You can change the instrument cluster fairly easily, but the part that concerns me is the "no message received from the Body Control Module". Darn near everything in the car goes through the BCM. You may have a shorted wire somewhere, or the short could be on the circuit board in the instrument cluster. If you can get a dealer to talk to you about it, you may want to try, but in my experience, most dealers just tell you to bring it in. Losers! Hope this helps