85 300TD - should the dome light come on when a rear door is opened? - PeachParts Mercedes-Benz Forum

Frazerjames · #1 02-03-2018, 08:35 PM

New to me 300TD and I’m really enjoying going through it to get everything up to snuff. Just a quick question about the dome light.

First, I know it works. It lights up when you open either front door. The rear doors - nope. I actually assumed they weren’t supposed to until I noticed the switches in the door jamb. Thinking they must be bad, I replaced them, yet, no dome light.

The question is, does the dome light turn on when you open the rear doors on the wagon? If not, what the hell are those switches for?

tangofox007 · #2 02-03-2018, 09:13 PM

The W123 sedans have a separate light for the front and rear doors.

Rogviler · #3 02-04-2018, 02:42 AM

On mine, also an '85, the rear doors turn on the rear dome light (by the hatch). Unfortunately my front dome light only works with the switch so I can't say if the back doors activate it also, but I can't imagine why it would.

-Rog

chrisgt · #4 02-04-2018, 11:13 AM

The back doors only turn on the light in the trunk, not the light in the front seats, this is proper operation.

If your front dome light is acting up, take it apart and clean (or rebuild) the switch contacts. It's a really stupid design prone to wearing out. I had to fabricate new contacts, of course I didn't take pictures...

MongooseGA · #5 02-04-2018, 11:56 AM

Quote:

Originally Posted by chrisgt

The back doors only turn on the light in the trunk, not the light in the front seats, this is proper operation.

If your front dome light is acting up, take it apart and clean (or rebuild) the switch contacts. It's a really stupid design prone to wearing out. I had to fabricate new contacts, of course I didn't take pictures...

This, but instead of trunk, he meant "back seats".

I just swapped out both of my dome lights with LED units. Not a bad improvement though, it does lack that warm glow. I'm sure there's a way, though outside of my electrical knowledge, to wire the the lights to both turn on at any door opening. That would be idea.

chrisgt · #6 02-04-2018, 12:00 PM

Quote:

Originally Posted by MongooseGA

This, but instead of trunk, he meant "back seats".

huh? The station wagon has a dome light in the trunk, not over the back seats. The sunroof slides into the headliner over the back seats which is why I'm guessing there isn't a light there.

The trunk and back doors both turn on the trunk light, as does the trunk light button on the dash.

Frazerjames · #7 02-06-2018, 11:49 AM

Quote:

Originally Posted by chrisgt

The trunk and back doors both turn on the trunk light, as does the trunk light button on the dash.

That's what I assume was supposed to happen. The back dome light does work, however, only when you turn the switch on manually. It doesn't seem to have that middle click that turns it on and off with the doors opening. Maybe it was was replaced at some point...

Frazerjames · #8 02-06-2018, 11:54 AM

Quote:

Originally Posted by chrisgt

the trunk light button on the dash.

Wait... There's a trunk light button on the dash??? How have I missed this?

chrisgt · #9 02-06-2018, 12:43 PM

I can't speak for every 300TD, but mine as well as this image I found on google have the button on the top left

Frazerjames · #10 02-06-2018, 02:07 PM

Quote:

Originally Posted by chrisgt

I can't speak for every 300TD, but mine as well as this image I found on google have the button on the top left

I DO have that button. It just doesn't seem to do anything... yet.

Also, I can't find a switch on the hatch to trigger the light to come on and off. Is it internal?

chrisgt · #11 02-06-2018, 04:57 PM

Quote:

Originally Posted by Frazerjames

I DO have that button. It just doesn't seem to do anything... yet.

Also, I can't find a switch on the hatch to trigger the light to come on and off. Is it internal?

I'm pretty sure it's in the latch assembly in the tailgate.

Stevo · #12 02-06-2018, 08:38 PM

The only way the "trunk" light well come on in my 85 euro TD is if I use the switch on the light fixture. I've had the car quite a while, I should look into that

MongooseGA · #13 02-06-2018, 10:50 PM

Quote:

Originally Posted by chrisgt

huh? The station wagon has a dome light in the trunk, not over the back seats. The sunroof slides into the headliner over the back seats which is why I'm guessing there isn't a light there.

The trunk and back doors both turn on the trunk light, as does the trunk light button on the dash.

My mistake, I didn't catch that it was a wagon in question. I read it as the doors would turn on the actual trunk light for a sedan

Frazerjames · #14 04-09-2018, 10:01 AM

Finally had a chance to open up the hatch door this weekend. Everything seems to be in workin order visually. There is what looks like a relay in there - I assume that’s for the wiper and not the Dome light. There IS some wiring going to the lock/latch. It looks in good condition and is definitely plugged in (I was hoping for an easy fix there).

Not sure where to go from here. Is there a switch or relay in that connector going to the latch?

vonsmog · #15 04-09-2018, 12:30 PM

I had to swap out the latch in my rear lid, as the light would only go on when it was closed. Open the lid and the light would go out. Swapped in another latch with good switch and it works as it should.