Cadillac: 89 deville dic/climat control trouble, distance computer, battery cables

Question
Hi Tom.  I have an 89 Sedan DeVille, 4.5 L engine, pretty basic model.  The car is my mom's, and has been sitting a lot.  Often, but intermittently, when I start it, the defroster comes on, hot, and the fuel/distance computer displays the letter "c", as does the climate control center.  I am also getting a service engine soon light.  The car has a new battery.  Also of note, the turn signals are slow to flash, and the windows operate very slow to return to the up position.  I'm showing 14.xx volts at the battery with the engine running.  Are the battery cables bad?  Other than that, I don't really have a clue what's going on.  Any help would be appreciated.

Thanks,

Charlie Siempelkamp

Answer
The letter you are seeing is it -c ?. If so, You need to replace the BODY CONTROL MODULE (BCM) computer. As far as the slow turn signals and windows, The battery may be  just low from not being driven much  or if it is the original battery, I would replace it.