Chrysler Repair: Concorde 1993 erratic trans, no guages, digital data communication, exact issue

Question
1993 concorde gauges started acting up, not work, then work,  then transmission went into limp, and would shift down lower abruptly. Car in good condition, trans served about 6 mo ago, no prob. Happened suddenly after tunred off;  had new ignit lock out in about year ago, windows, etc fine. lights for gears went on erratically before out; engine runs fine

Answer
Hi Bruce,
It appears to me that the digital data communication across the bus network is experiencing communication problems. The gauges and the electronic control of the transmission depend upon that data bus to be functionning.
You can do a diagnostic test on the system to see if that problem has been recongized by the engine controller and stored as a fault code number in its memory. Use the ignition key:"on-off-on-off-on and leave on" doing that in 5 seconds or less elapsed time. Then watch the check engine light which remains "on" to begin to flash, pause, flash, etc. Count the number of flashes before each pause, then repeat for accuracy. Then group the numbers in pairs in the order of appearance to form 2-digit fault code numbers. The last code will be 55 which means end of readout.
The code 66 is the one about a data bus problem. There is a decoder list at www.allpar.com/fix/codes.html for other numbers. If you have a data bus problem then there is a readout plug under the dash to which a Chrysler Diagnostic Readout Box II attaches and which will allow a knowledgeable tech to  diagnose the exact issue with the bus and also with the transmission. I have the manual for that process if you run into problems finding someone with the reader.
You might also check your battery connections and also the possibility that there is a flakey internal battery  connection within that is putting noise on the electrical system. That too has caused similar problems.
Let me know what you find and how I might be of further help.
Roland