I have a 1980 300SD and have two problems:

1. The driver's side seat belt doesn't retract. I have a spare parts 300SD that has a good belt and would like to take it out and reinstall it in the good car. Is it a DIY project? If so, how do I get the belt removed?

2. The courtesy light didn't come on when the passenger's door was open. When I inspected, I found that the door switch is not there. Just a rectangular hole approx. 1/2" square. Has anybody every heard of this switch being missing or falling off? And if the prior owner had it removed or lost it, how hard is it to replace?

Thanks.