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'78 280SE Lights and Parking lights stay ON with light switch off

Started by jmperkins, 25 September 2012, 10:59 AM


As I am out of town, my wife calls to tell me the headlights and parking lights will not turn off on her '78 US 280SE regardless of the light switch position and ignition switch.

Her associate doesn't have a wrench to disconnect the battery to save her having to get a jump. I'm suggesting he pull fuses 5,7,13 and 14 for now to save the battery assuming that will turn off the lights.

Could this be anything other than a bad light switch (maybe bad connection at switch)? If there is a relay for the lights, does anyone know where it is located?

Just told that removing the fuses 5,7, 13, 14 didn't help. Stuck relay? located where?



You can also try disconneting the cables from light assemlies. On standard non-American lights this is easy. Back lights should be straight-forward.


Certainly disconnecting the wires would work, agreed. I'm thinking the relay is a multi-purpose one that is one of the 2 front ones in the fuse box. Perhaps it got too hot due to age and stuck.

jmperkins my wife tells me that she disconnected the wires from the little back box and now her turn signals don't work but her parking lights are off now but I haven't confirmed what the headlights are doing now.

Is that black box with all kind of wires coming into it function as the turn signal relay but must do other things to as she says with it disconnected, no power to the radio?


My wife disconnected what turned out to be the turn signal flasher relay, a 3 prong black exterior colored relay part #BGE 201.269 made by SWF.

I can't find a replacement relay anywhere. If anyone has a working one they want to sell, shoot me an email to Otherwise, I will try Pick N' Pull!

Joe Perkins
Berkeley, CA temporarily working/living in St Louis, MO


Just an FYI Follow up; I found a replacement/used turn signal relay on eBay, part # Bosch 0 335 200 007. All is working now.

This had nothing to do with the headlights staying on (I think my wife dreamed up that one)  but with the old relay installed, the flashers would blink even with the key in the off position.

Happy Holidays to ALL!


That's good to know for future reference. Thanks for posting.