Wiring, a general question

[dmtinker]

I have an 82 300SD which I've had about 2 weeks. I am having a lot of problems with the wiring. I wanted to know if this is generally the case. The shop has had to rewire the drivers seat due to cracked/bad wiring at the door jam. I was not happy with the job and brought it back. Some of the splices showed copper and the put in no weather protection on the wires.

I've also had problems with the dash lights and the right side marker lights. Are the Mercedes of this era notorious for bad wiring?