Hi everyone! New 240 owner here (1992 240 DL with around 200,000 miles). I’m 19 and though I’ve owned a car since age 15, this is my first car I’ve started working on myself (beyond oil changes and general maintenance) as a project.

Anyways, I noticed both tail light boards were being super finicky as they tend to be, so I ordered new boards and installed the right one. The left one has a broken board, but I repaired it with some solder, so I’ve left the new left board as a spare. All lights function except for the tail/brake light and the fog lamp on the right side. When the brakes are off, the brake/tail runs bright, and when the brakes are on, it dims. I’ve tried several different sockets and bulbs for both lights and that didn’t seem to fix it. The brake/tail also gets EXTREMELY hot as I would expect since it’s running bright. For now, I removed it until I can figure out what is wrong, hopefully with your help.

Additionally, this morning on the way to work, I noticed the seatbelt warning light was coming on either randomly at high speed or under heavy braking. There is a relay dangling by the pedals so I’m wondering if that has anything to do with it.

Finally, I also noticed the driver door does not trigger the dome light like the other 3 doors do. Not sure if this is normal.

Thank you in advance!

Here is the link to a video of the tail light issue https://youtu.be/tjHUFyInj4o

 

The brake/parking bulb holder on the 86+240s are different left and right. A white bulb holder goes on the right side, a black one on the left - they are wired differently. What I suggest and have done to hundreds of cars - is move the brake light to the fog lamp position - that's where they were through 1985. You will eliminate the melted housing/circuit board/erratic brake light problems with that simple move (do you ever use your rear fog lights? - if so move the wire to where the brake lights were and have them be erratic!)

Simply move the brake light wire in the multi connector on the back of the taillamps to send 12v to the upper inner bulbs.

For the dome light switch for the driver door - swap the drivers with maybe the left rear door to see if that fixes it. A free fix.