Ghost in The Machine....Short somewhere in seat adjustment
 

I am replacing the seat basket on the drivers seat in my dads 86' 560 SEL, but I am having a terribly hard time because of a short somewhere in the system. I can adjust the seat backwards and I can adjust the back rest without issues, but If I try to move the seat forwards past a certain point the fuse blows every single time. I need to move the seat forward in order to access one of the screws to remove the basket frame, so it's particularly frustrating.

I want to identify and fix the short, but I am not sure how to approach it. Visually I cannot see any wires that are frayed or busted (nothing cut from the bad seat basket either). How can I test continuity on the various lines running to the seat motor?

I would look for something jamming the mechanism rather than a short. If it travels all the way to a certain point then blows the fuse, it is probably hitting a busted gear tooth or something that is overloading the motor.

Good point. I'll give it my best but I don't believe there is a mechanical way to move the seat...it has to be moved electrically. This means putting the seat back in the car and hooking it up and once its in there it's very hard to see whats going on.

I swear...I would love to find an old 126 with manual windows, manual seats and the manual sunroof. It would be worth so much more in my eyes

Perhaps you could make a few jumper wires so you can play with the seat while it's still out of the car.

With a wiring diagram, you could figure out which terminals go to which motors on the seat, and you could apply voltage manually to move the seat while it's still on your bench.......

I'd love to except I do not have a wiring diagram for this car. Ideally I would just swap it out with other seat motors and frames that I have(from seats acquired at the junkyard...it's where I got the basket)...but alas they have a different pin set. I think on the car I'm working on it's an 8x2 pin set for the main wiring harness that hooks up to the motors. On the other seat I have it's 7x2...weird. I believe many of the later 126 chassis had varying options that would have had a direct impact on the wiring in this area (seat memory etc.)

Would you happen to have a wiring diagram or know where I could get one? Many thanks for your help