Electrical problems
 

I have an 85 911 and I am not able to lock the doors from the outside with the key. I can unlock the doors from the outside but not lock them. Also the interior lights above the door will come on when you open the door but if you turn them on manually they do not work. Any help would be much appreciated -- Thanks Tim

Tim, The rocker switch for the dome light is corroded. The light lens pops off to get to the contacts. clean the contacts with an ink eraser, & electrical cleaner. The lock is more time consuming. You might get lucky by just lubing it, if not the door panel has to be removed to inspect the linkage to see whats come lose or is worn out. Get a copy of 101 Projects, & a Bently manual to see the schematics to help fix these types of problems. I find the pictures in these publications a great help too.

The dome light uses chassis ground from a clip on the light housing