[GMAC454]

I would look into the BCM? the Body Control module controls all of the functions you are talking about.
The fix is usually the BCM - Body Control Module. this little beast of a circuit board does just about everything !!!!! it controls your security system if you have one, it controls the rear wiper, the front wipers and all the related delays, the security system, elect locks, etc.... and electronic signaling associated with this stuff. I have gone thru the entire electrical schematics on this thing. the module is about 385.00 bucks. Ouch! thats alot just to fix your wipers, or headlights.
But what i did was call a reputable auto salvage yard and had them do a computer search for my make and model '96 grand caravan for a BCM. they found one without issue and it was 100.00 bucks including shipping. some of the BCM's need to be programmed (flashed) by the dealership this is about 65.00 bucks. but i know for a fact that the '96-'99 are plug and play no flash required. i pulled my old one slammed the new one home and "click" my wipers and locks and etc.... work perfect!!!!!!!!!!!!

the BCM is located under the DASH on the drivers side right behind the fuse plate. it is fairly easy to get out. there are just a few 9 or 10mm bolts that hold it in place and then it slides up on a couple pegs and the bolts just hold it in place. look at the one you picked up and you will see where the bolts are. dont forget the very top one toward the driver door, you will need an extension about 8 inches to get it. also if you remove the code testing plug-in that sits under the lip of the dash it will save you a few scars (believe me) the screws protrude right where you will be snaking your hand up and through. I feel it is a simple fix and the only criteria for ordering are if you have a security system or power locks or a combo of them. hope this helps you save some money fixing this.
thanks
GMAC454