Curious, before I dig in, if anyone has a place to start for me to figure out a strange electrical issue in my 83 300SD.

When I turn the key to start the car to the "glow plug" mode (before you crank), my other dash warning lights don't come on. Rarely they might, but 99.9% of the time they do not. The glow plug dash light does come on and turn off correctly. It seems there is a drain going on right now on the battery too. The horn seems to be very intermittent and sometimes blower motor doesn't want to work.

This seems to have started just recently (I have been fixing up the car). I changed the glow plugs and glow plug relay last weekend and right after that is when it started. The glow plug relay was pulled from a junk SD, but was a year or two newer and the ID numbers didn't match (junk yard said to bring back if it didn't work so I wasn't too worried). But, the relay seems to work fine for starting the car so I thought it should be okay.

I was planning on putting the old glow plug relay back in, changing the very sloppy ignition switch, and check the fuse connections under the hood to make sure they were making good contact. But, after that....I am not sure what to look for or check.

I am wondering if there is a relay somewhere that might be worth checking or if there is a "fusible link" somewhere in these cars (had a 525 bmw with a bad fusible link before so I know how gremlinish they can be).

I have "in laws" in town now.......so this would be a GREAT time for me to stay busy working on the car! lol

Does anyone have a clue?