Electrical troubleshooting

Guys,

I'm flying blind on this topic as I know next to nothing about testing and wiring fixes. I've finally got my 79 280CE running well and all mechanical issues solved. But now, some electrical items have popped up and I don't know how to proceed. Last week, one of the two lights on the dash cluster quit and I also noticed the right rear side marker light was out. Over the weekend, I stopped at MB and bought replacement bulbs. first I pulled the rear light, which didn't look burned out, and sure enough the replacement doesn't work either...bummer. Next I pulled the dash cluster, and after regluing the front glass, which fell off (yes I was pulling correctly), I replaced the bulb to no avail. Still didn't light back up. Also the front dome light will come on with the integral switch, but not the rear, and neither lights when the doors are opened. It seems unlikely that both doorframe switches would be bad, but I can't figure out how they come out to test/replace anyway.

If it is relevant, the car came from Florida and I had other electrical issues that were resolved by cleaning fuse contacts, with no recurring problems there.

At bare minimum I'd like to get the dash light going again as 123's were never too bright anyway, and I can't see the gauges after dark.

Ideas? Thanks.

[300SDog]

Salty air in Florida corroding connections?? Maybe all you have to do is clean sockets and contacts..... #220 fine sandpaper, small brass brush and electric parts cleaner should do the job. Wiring harnesses themselves NEVER have problems unless they get toasted being too close to the engine after 30 yrs.

Door switch buttons pull straight out - just grab em by the nub collar (not the button) or pry their edges with screwdriver.... and yes, they are socketed to the wiring harness behind.

Rule on ordinary non-computerized MB electrical components is they are "rebuildable" by cleaning them and/or judiciously bending contacts for tighter connection at places like bulb positive contact copper flaps...... exception to the 'rebuild rule' might be the notorious dashlight dimmer switch that can be bypassed and hotwired from one end to the other. In more than 20 yrs, I've never seen a vintage MB with properly functioning dashlight dimmer switch - but why should anyone care so long as the dash lights arent blacked out entirely?

You can use electrical parts cleaner liberally - its not oily and leaves no residue....... just gotta poke and probe each faulty component. Forget about the shop manual electrical wiring schematic - it will do you no good.

Thanks Dieseldog. It was 9 degrees this AM, and I drove the Benz to work, first time I drove it in cold weather. Florida car said "What's this?" but after her juices started flowing, ran fine. Heater probably hadn't ever been used much. I need to wait for warmer weather to start pulling stuff apart and checking connections, not just for my fingers sake, but old plastic can get pretty brittle in the cold.