It all started after I installed my aftermarket radio(i think, becasue I did this as soon as I bought my 83 240dl), the cigarette lighter gives neglagible power, just enough to light up the LED on the inserted item but not enough to power anything, and it will only work with the light's on, as well when I plug it in the rear defrost switch light's up. The other part of it is when I turn the flasher's on the switch doesn't light up and the rear defrost switch light blink's with the flashers. The light's for the climate control wont come on either; the glove box light is also disfunctional, as is the little white light above the rear ashtray, even after changing the bulb and cleaning the connectors, sure hope some one has an idea on this one

 

The way to figure out this one is to get a wiring diagram and measure the voltage drop along the affected circuit.

 

I found one loose ground that attaches to the cigarette lighter, plug'd that in and the console light's work, but the rear defrost switch doesnt light up, would this mean that it's not working now? before it used to come on when I pushed in the cigarette lighter and then go off when i pulled it out.

 

On my rear window defrost power comes first thruough ign switch then through two fuses no 11 and no12. from fuse 11 it goes down a BL wire to 12 minute relay. from fuse 12 it goes down a BL/Y wire to dash switch. Switch on dash starts relay and closed contacts on relay light the indicator light. So if your light is out either bulb is burned out or your rear defroster is not working. Your car seems to be wired strangely. Maybe time to get a wiring diagram and sort it out.