Hello from new member and rear hatch electrical question

[Colo300tdt]

Hello everyone,
My name is Eric Everett and I just joined today. Its a great forum you all have here. What an incredible resource for all MB enthusiasts!

The car is a 87 300 TD wagon. Last weekend the rear wiper would come on when I would I turned the rear window defrost on. Also the wiper and washer for the rear window would work intermittently. After searching the posts, I checked the relay on the back hatch and all other connections as well as replaced the associated fuses (Thanks Brian C, and others). These all were clean and in solid connection. I then turned on the wiper swich and tried the gate in various degrees of openness and found that the wiper, etc. only worked when the gate was less than 50% open to fully closed.

I am now curious about a potential problem where the wires flex at the hinge of the gate and wondering if it is possible for a problem (crossed bare/worn wires) to be occuring there causing these symptoms? I removed the headliner trim there and can see the wiring on both passenger and driver sides. It looks like the passenger side has the vac line, washer line and a couple of colored bundles of wires. Any ideas on which ones control the defrost or wiper? how to test these?

Many thanks in advance,
Eric
Colo300TDT

[JimmyL]

I'm not really familiar with the '87 wagons, but wanted to say welcome. Somebody will have your info. Those are fairly rare cars compared to alot of the others we yak about around here.