Mw128

I know there is a ton of topic relating to wiper issues, but I cannot figure out what’s going on with my car, and my issues are different than what I seem to come across in my research, and I hope someone can shed some light. I have a 98 e320 wagon with a rear wiper that has not worked since I’ve owned the car (not long) and living in Colorado I really need this working for winter. The dash switch seems unresponsive when pressed (no led) no wipe, no washer pump activity, no clicks, nothing. Wiper doesn’t wipe when put into reverse when front wiper is on like I remember my previous model doing, so I replaced the dash switch, still same issue. Replaced relay on wiper motor, still nothing. Checked all fuses, all is good.. My car has 315k miles, but every single thing works, except my rear wiper system, and it’s driving me crazy. Could a bad motor cause a power disconnect that would result in total inactivity, should I replace it?

Eurow

You can supply 12v directly to the rear wiper motor to check it's function and to rule it out as the culprit.