01 Town & Country Electrical Mystery

I own a '01 Town & Country Limited with sporatic electrical glitches. Just
about everytime I drive the van some weird electrical glitch comes up,
however, the glitch is usually different every time. Ex: used auto window
down on drivers side to get mail, went to roll window back up and it
wouldn't go back up. Shut car off, restarted it and window would go back
up.

On occassion the auto doors will work, others they won't. Same with auto
hatch. One day car would'nt go into reverse until shut car off and
restarted.

One last item is that after the car is shut down a high pitch sound that
gains in intensity then tapers off is heard from the engine block near the
serpentine belt. The noise sometimes comes after 10 seconds, sometimes
after 2 minutes, and lasts for approximately 5 seconds. It is not the
cooling fan! as so many have suggested. Don't know whether it is related
to the funky electrical problem or not.

From a novice's perspective it appears that either I have a ground issue
or some type of module issue. I have checked the main grounding points
and found nothing out of the ordinary. HELP! How do I troubleshoot this
beast? Because it is a Limited it is loaded with electrical gadgets, e.g.
auto temperature, dvd, traction control, 4 abs, auto ride, etc...which
doesn't help my cause. Could the system be overloaded?

 

The car has multiple grounds and one could be bad. Or it could be a flakey
battery. Those are the 2 cheap things to try first.