The wire that runs from the headlight switch to the 3rd brake lamp on that car is black/purple/white.

Comes out of the headlight switch on wiring connector "A" pin # 5 and goes directly to the connector on the lamp.

Should have power if you have the key on & brake pedal depressed.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

AWESOME. I'll check this later this evening after work. This is very helpful.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

That is so weird that the 3rd brake light power would come out of the headlight switch of all things.

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

Like I said the headlight switch IS the bulb-out monitor & fuse box.

__________________
MERCEDES Benz Master Guild Technician (6 TIMES)
ASE Master Technician
Mercedes Benz Star Technician (2 times)
44 years foreign automotive repair
27 Years M.B. Shop foreman (dealer)
MB technical information Specialist (15 years)
190E 2.3 16V ITS SCCA race car (sold)
1986 190E 2.3 16V 2.5 (sold)
Retired Moderator

Figured this one out. The terminals on the fixture are not the end of the line, as there is a slide contact that can corrode. There's a little tab on the fixture that you depress upwards, then you can slide the whole thing out and see the contacts. One of mine was corroded. I wet sanded it with some electrical contact cleaner, and all is well. See this eBay picture; the one for sale sadly has both slide contacts badly corroded:

__________________
08 W251 R350
97 W210 E320
91 W124 300E
86 W126 560SEL
85 W126 380SE Silver
85 W126 380SE Cranberry
79 W123 250
78 W123 280E
75 W114 280

I just bought a new 3rd brake light assembly (210 82 007568F95) from ********AZ for $47.60 because my light assembly housing in my 1997 E300D was broken and the red lens wasn’t looking so good. It even came with a bulb installed! I looked up some threads on light assembly replacement to make sure it still worked like my W124 did. I found the early W210s had a VERY COMMON problem with these light assemblies, particularly on 1997 models, which made me curious as to what I would find. I went outside in the dark to swap mine out.

I found what most owners of early W210 bodies have found. For some reason the brake light assembly and the corresponding mounting assembly integrated into the rear shelf don’t have a properly seated connection. I’m not an electrician, but there must be a short or too much power going through a poor connection. It actually melts the plastic on the mounting assembly. (see attachment) I tried to get a pick in there to raise up the connection plate, but the plastic was melted around it. I’m going to call the dealership tomorrow to see if the mounting assembly in the parcel shelf is available.

I did mount my new light assembly. I pulled the connector down on the one side to try and ensure a good connection on the bad mount. Also, the two channels that the light assembly slides into was slightly melted and deformed (see attachment), so sliding the light assembly on the mount was difficult, but worked. The brake light is nice and bright, so I’ll use it until I find a mount assembly for the parcel shelf.

More 3rd brake light threads:
http://www.peachparts.com/shopforum/tech-help/339032-96-w210-e300-no-power-3rd-brake-lite.html
http://www.peachparts.com/shopforum/tech-help/333956-intermittent-power-3rd-brake-light-w210-1997-e420.html

Attached Thumbnails

 

__________________
NOW: 2017 C43 AMG, 2006 Wrangler Unlimited Rubicon, 1966 230SL, 1980 450SL (for sale!)
PAST: 2006 C230, 1997 E300D, 1994 E420, 1994 Neon Spt Cpe, 1984 300ZX, 1983 Celica GT, 1976 Electra Limited, 1984 Honda Nighthawk 650, 1979 Suzuki PE175, 1978 Suzuki DS100
www.mbca.org - www.sl113.org - www.ohio4x4.com