So on my 88 240DL, back lights are always on when the car is on. Once I turn the car off the lights turn off also, but if I press the brake pedal, the lights turn on (with the car still turned off).

What can that be, My guess is wiring somewhere? Maybe constant power wire is connected to the ignition wire or something similar? Can it be the fuse, or a relay?

Thx!

 

Sounds to me that you have a wire crossed somewhere between the brake & backup lights. I believe on the 240 the brake lights work even if the key is turned off. I don't have a helper right now so I can't check my own to verify that it is true.

 

Yea I dont have a reverse light either... What wires are those? Where are they located, in the trunk?

 

the reverse light switch is in the same module as the park/neutral safety switch, buried in the shifter box. the wire goes through pin 9 of a 3x3 connector behind the fuse panel, down the drivers side floor sills back to the left tail light, then across to the right tail light. my diagram shows thats a black wire for an 87/88 240.

indeed, 240 brake lights work even with the ignition off. red wire from the positive terminal goes to fuses 6-7-8-9-10. fuse 7, green-yellow wire goes to the brake switch (on the brake pedal arm), and a blue-red wire goes from that swittch to the bulb-out module pin 9. BO module pin 10 is a yellow-grey wire that goes to the left brake light, BO module pin 11 has a yellow wire to the right brake light, and BO module pin 5 has a blue0-black wire to the 3rd brake light.

I'd check the grounds in the tail light clusters, there should be a black wire to a ground screw right near the each tail cluster.

 

Ok I will check the grounds for sure and go from there. Looks like previous owner tempered with wires, I went to local pick an pull and cut off the tail light harness so I can maybe splice it and plug it in the tail light since now the wires are going straight to individual light bulb sockets...

Thx

 

they probably did that direct wire job because the flex circuit board on hte tail light was failing.

is there a bunch of hacked wiring under the dash too?

 

Yea thats possible but I remember everything working when I got the car first. I changed the fuse for the back lights, I think #7 but that didnt help.

I just checked the grounds and they look nice and clean. And the wires under the dash are not hacked either...