Just purchased a 78' 300D. Battery keeps dying, ignition is screwed. When I crank the key, it does'nt pop back over and stays in the far right position (it keeps cranking the starter and does'nt allow alternator to recharge the battery?) Only Way I can get it to run is after I jump the car, I turn the key all the way over to off position but the engine does'nt die. It keeps going, and I have no electronics of course. I turn off the engine by pulling the throttle linkage to the passenger's side.

My ignition switch is bad?!?!??

Also, once I got home I realized there were no brake lights and diagnosed the problem. Due to there not even being wires going to brake switch, they don't work. Which I find very strange, considering the fact that there is absolutely no wire under the dash at all for the switch! One more thing. It seems the oil needs a changingreal bad, it is quite dirty. What would someone recommend for me to use? The engine has 109,000 miles.

 

You can replace either the tumbler or electric portion of the switch separetly.
Diesel motor oil looks dirty 20 miles after a change.
Get that brake light fixed!
Engine shutdown may be a switch and/or vacuum issue.