Help: Problem after installing 05 Tail Lights on 02 C320
Thread Starter
Super Member
Joined: Jul 2015
Posts: 795
Likes: 189
From: San Diego, CA
2016 E350 Sport; Mom Wrecked the 2008 E350; sold the 2002 C320
Help: Problem after installing 05 Tail Lights on 02 C320
I have a 2002 C320 (pre facelift). I upgraded the tail light housings using ones from a 2005 C240. I followed this DIY: https://mbworld.org/forums/c-class-w...203-sedan.html
except that my wiring was slightly different. In the DIY thread, it shows different wire colors for the left side and right side. On my C320, the color scheme is identical for the left and right (on my car, the color scheme on both sides is the same as for left side as follows):
Driver side:
Brown = ground (pin #6)
blk/grey = running light (pin #7 and pin #1)
blk/white = turn signal (pin #5)
blk/red = brake light (pin #4)
grey/blue = reverse (pin #3)
wht/green = rear fog (pin #2)
Wiring on the left side was a perfect match. On the right side, I wired it identically as above, except that on the new 7 pin harness, pin #2 is empty and I left the white/green wire (rear fog) disconnected on the right side.
The lights worked fine for the past couple of weeks. However, I now have 2 malfunctions - Right tail light out and bulb out, using backup lights (where it substitutes the brake lights for tail lights). Now the normal tail lights on the bottom row don't illuminate.
I replaced the bulbs but no change. Today I took it to my local MBZ specialist, they replaced the bulbs again, but still the malfunction warnings don't clear and my regular tail lights are not working. They said they would have to run a full diagnostic (which is going to run me ~$150)
Before I decide to let them run a full diagnostic, I wanted to see I I can get some help/guidance here which would be greatly appreciated.
except that my wiring was slightly different. In the DIY thread, it shows different wire colors for the left side and right side. On my C320, the color scheme is identical for the left and right (on my car, the color scheme on both sides is the same as for left side as follows):
Driver side:
Brown = ground (pin #6)
blk/grey = running light (pin #7 and pin #1)
blk/white = turn signal (pin #5)
blk/red = brake light (pin #4)
grey/blue = reverse (pin #3)
wht/green = rear fog (pin #2)
Wiring on the left side was a perfect match. On the right side, I wired it identically as above, except that on the new 7 pin harness, pin #2 is empty and I left the white/green wire (rear fog) disconnected on the right side.
The lights worked fine for the past couple of weeks. However, I now have 2 malfunctions - Right tail light out and bulb out, using backup lights (where it substitutes the brake lights for tail lights). Now the normal tail lights on the bottom row don't illuminate.
I replaced the bulbs but no change. Today I took it to my local MBZ specialist, they replaced the bulbs again, but still the malfunction warnings don't clear and my regular tail lights are not working. They said they would have to run a full diagnostic (which is going to run me ~$150)
Before I decide to let them run a full diagnostic, I wanted to see I I can get some help/guidance here which would be greatly appreciated.
Thread Starter
Super Member
Joined: Jul 2015
Posts: 795
Likes: 189
From: San Diego, CA
2016 E350 Sport; Mom Wrecked the 2008 E350; sold the 2002 C320
Ok got it figured out (well, the Indy did)
Problem solved. Unbeknownst to me until today (and thankfully), my car had the supplemental harnesses from the 2008 TSB for premature bulb failure (the harness that reduces voltage by 1 volt to prevent premature bulb failure). The resistors were burned out (I assume that this was a result of splicing pins 1 & 7 on each side, which probably overloaded them).
The indy cut the resistors out and now everything is back to normal still using the '05 tail lights.
Also nice to know the original harness is still intact. Nice $112 lesson...
The indy cut the resistors out and now everything is back to normal still using the '05 tail lights.
Also nice to know the original harness is still intact. Nice $112 lesson...
