If you have a late 80s, early 90s Ford truck where the windshield wipers will only work on High, not on low or interval, then you may need this part. It was purchased used and I tested it out as functional in my 1991 F250. I subsequently repaired my original part and put it back in the truck. That truck has now sold and this part is surplus. Selling "as is". Part number on the casing is 17C476 -