My wife's 99 mystique has developed multiple, concurrent
failures with the rear defrost switch, horn and intermittant
wipers. As well the dome light will come on and stay on at times
. Any thought's? I am checking the fusible links under the
drivers side cowling mentioned in an earlier post. All fuses and
relays in the boxes seem fine.

So I couldn't find anything that would cause all the problems so
I was going to replace the switches. I replaced the stereo so we
would have a CD player and guess what happened. Everything
works except the horn, a bad ground under the car I believe.
unfortunaely the interior lights don't work when the front doors
open now. There were no fusable links under the cowling on
the Mystique.

I have been having the same problem with my 96 mystique. I thought it might be a fuse problem but they seem fine. What should I check next?

Your guess is as good as mine. I also removed all the door pins
for the interior lights and removed the corrosion in the hole,
lubed the pins and reinstalled them. As you read my interior
lights don't work when the front doors open, but the problem of
them staying on and killing the battery has stopped. My only
advice is to fix something that is not broken and everything
else may change. Good luck.