On our 1995 Transport 3.8L, I go to the right rear wheel well area of the cargo section and remove the panel. I unplug and reconnect the connectors at the circuit board for the sliding door. I also unplug and re-seat the other connectors related as well. I have done this so often, I can perform this in about 2 minutes. Any time a seat belt gets in the door sliding area probably confuses the electronics for the sliding door. Another way that is used on the 95 TS is removing the fuse in the fuse panel for the sliding door(glove box area?) for a few minutes and re-seating. Not certain which fuse.(brake lights maybe)
Our windshield wipers were acting erratic. I replaced the circuit board for the wiper motor. LMP (member) found re-soldering the solder joints at the connector for the circuit board would solve intermittent problems. I have not
had any experience with wipers working on High only. Possibly the same answer. Good Luck