Electric sunroof partial close
 

My electric sunroof opens just fine but closes up to about 2/3 ten i have to manually help it along does this sound like lack of lubrication on the rails or a SR motor problem this is on a 1983 W123 240D

Sounds like it needs lubrication and possibly alignment. They often get unreliable in the colder months because of the lube getting stiff. Winter is a good time to clean and put fresh lube on the cable, tracks and feet. Mercedes Source Dot Com has instructions, tools and lube as a kit. Many think his stuff is overpriced but there are no surprises when you get one of his kits.

Try not to let it "grind". The motors can take a beating but there is a large fiber gear in the drive that engages the spiral winding on the cable. If it gets stripped, they are hard to find.