First check if the washer motor works. If it does not, the place to start is with what both systems have in common. That's the 12 volt supply / fuse circuit. Grounds aren't suspect at this time because each motor uses a different one.
There is a relay built into the switch assembly, but it is related to the intermittent wipe circuit.
The fastest way to test the switch is to use an old-fashioned, inexpensive test light with a bulb inside. To be most accurate, the readings should be taken with everything plugged in. If you have to disconnect a connector to take a reading, digital voltmeters can give false information where test lights are much less likely to do so.
Go to the wiper motor and check for voltage on the blue / black wire when the switch is in the "low" setting. Next, check for voltage on the blue / orange wire when the switch is in the "high" setting. Let me know what you find there.
If you have both of those voltages, check if the wiper motor is bolted to a plate that is mounted to the car on rubber bushings. When that is done, there will be a metal ground strap under one of the bolt heads. There can be arcing under that strap that breaks the ground circuit. The wiper motor won't run in either speed, but the washer motor will run normally. A clue can often be found by tugging up gently on a wiper arm. That can twist the motor just enough for that ground strap to make a temporary connection. The motor might run for a couple of seconds or a lot longer. If you find that, let me know, then I can describe how to verify that cause, but it requires the defect to be present during testing. I repair those by attaching a new ground wire. I can describe that in more detail if necessary.
Oct 10, 2025 at 6:54 PM
