I replaced the wiper linkage bushings on my 92 Dakota today. After reassembly, on high speed the wipers move slow on the wipe cycle, and fast on the return or park cycle. I don't know if it happened on low speed. I have disassembled it again to replace a squeaky bushing. I didn't pull the motor, or do anything to the electric circuit. This is new behavior, as the speed of the wipers was as it should be before I worked on it.

Does anyone know what would cause this?