I had one of the taillights assemblies out while I was doing bodywork and noticed that there was not any socket in this taillight.

Kinda weird.

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85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

That is normal for US 123s.

The socket is for the rear high intensity fog lamp that is actuated when pulling the light switch out to the second stop. If you pull the knob off you will notice a light socket there, that is supposed to light up with the knob pulled out to the second stop and makes the hub of the switch knob glow orange.

The Feds don't like that feature or at least they did not back in the 80s so the US models were not equipped.

I think several members have added extra brake/tail sockets salvaged from a parts car and wired in parallel to the other brake/tail bulb. On a 123 that is a good thing given there is only one brake light per side and no CHMSL.

Or you can get hold of the Euro wiring diagram and hook up the rear fog feature. I believe the US light switch has the necessary contact and the indicator bulb socket in the knob stem is active. It uses the same type bulb as the turn signal. This goes on the road side (left for US), the other side remains blank.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I performed this upgrade on Coda and have the parts for the 87 Champagne. Here's the write-up done by Chad:
http://www.peachparts.com/shopforum/diesel-discussion/287882-brake-light-upgrade-w123.html

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daw_two
Germantown, TN

Links:
Sold last car --- 05/2012 1984 300D Light Ivory, Red interior
Cluster Needles Paint
New Old Stock (NOS) parts

Past:
3/2008 1986 300SDL "Coda"
04/2010 1965 190D(c) "Ben"
& many more

i did the upgrade on my 83SD. will the upgrade affect the operation of the bulb-out light on the GEN 2's? i want to do the upgrade on my 91 SEL but wasn't sure...

__________________
1983 300SD (daily driver)
1991 420SEL (work in progress)
1979 300SD (future replacement for 83 SD)

RIP:
1983 300SD (totalled)
1986 420SEL

Hmm, I'm not sure that will work, the relay is probably calibrated for the draw of one bulb. If you put 2 in parallel that is double the current. Not sure what the relay thinks of that.

If it accepts double the current and still gives a good indication then you would have to lose both bulbs to get a fault. But I'm worried you might smoke the sensor in the relay with double load.

I'm pretty sure every bulb on the outside gets its own channel in the bulb monitor.

__________________
The OM 642/722.9 powered family
Still going strong
2014 ML350 Bluetec (wife's DD)
2013 E350 Bluetec (my DD)

both my kids cars went to junkyard in 2023
2008 ML320 CDI (Older son’s DD) fatal transmission failure, water soaked/fried rear SAM, numerous other issues, just too far gone to save (165k miles)
2008 E320 Bluetec (Younger son's DD) injector failed open and diluted oil with diesel, spun main bearings (240k miles)

1998 E300DT sold to TimFreeh
1987 300TD sold to vstech

I added extra brake lights to these spots, on my 300D w123.



Some members have modified theirs to function the same way Euro w123's do, by adding a rear fog light in the tail light on the same side as the driver, and wiring it up.

However, my observation is that on some units these innermost lenses do not have a proper reflector to bounce off the 21W brake lights, but some do. What happens is these spots will appear slightly darker due to less reflected light.

I did the brake light up grade several years ago on both my 123 sedans.

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1985 Euro 240D 5 spd 140K
1979 240D 5 spd, 40K on engine rebuild
1994 Dodge/Cummins, 5 spd, 121K
1964 Allice Chalmers D15 tractor
2014 Kubota L3800 tractor
1964 VW bug

"Lifes too short to drive a boring car"

I really don't have that much interest in adding a brighter fog tail light. but wouldn't mind adding either more regular taillights, brake lights or turnsignals. I think having an additional brake light might add the most safety.

Thanks.

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

I did the up grade before discovered the forum. wonderecd why there was no light on each side. got a broken light from a junk yard and canablised some socket and soldered them in.

It sure lights up the night sky.

There was a thread last year of an up graded brighter bulb, Iam going to do a search and post it. 10-23. (standby)

Found it.


http://www.peachparts.com/shopforum/diesel-discussion/297456-%246-brighter-w126-brake-lights.html

Charlie

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there were three HP ratings on the OM616...

1) Not much power
2) Even less power
3) Not nearly enough power!! 240D w/auto

Anyone that thinks a 240D is slow drives too fast.

80 240D Naturally Exasperated, 4-Spd 388k DD 150mph spedo 3:58 Diff

We are advised to NOT judge ALL Muslims by the actions of a few lunatics, but we are encouraged to judge ALL gun owners by the actions of a few lunatics. Funny how that works

I tested the main light switch on the way home. There is a second "out" position on it. Of course without wiring....

__________________
85 Merc 300D - Unwinding 31 years of wear
86 VW TD
Mahindra Diesel
Iseki Diesel

In 2007 I didn't own a diesel.

The second detent, as called in the manual, is for rear fog lights. European and rest-of-world models had them. US models did not.

yeah that's what i was worried about. maybe if i wire-in a diode it might be ok; not really worried if one of the "upgrade" brake light bulb goes out and the indicator doesn't show it...

__________________
1983 300SD (daily driver)
1991 420SEL (work in progress)
1979 300SD (future replacement for 83 SD)

RIP:
1983 300SD (totalled)
1986 420SEL