300e needs parking lights to start
 

92 300e (4matic) need the parking light turned on for the engine to start, can shut light off and car keeps running, but if I turn key without the light on, engine will not attempt to start???

It would appear that the starter circuit is getting either a voltage or ground thru the bulbs when the switch is on. Once the engine is running the starting circuit is not needed

light off no start
 

When you try to start the engine with the light off, does the engine turn over? If the engine turns over but fails to start we could be looking at a lack of spark or fuel?

If the engine doesn't turn over there could be an ignition relay at fault which is using the light circuit as a ground.