With my Euro corner lights (Bosch), I simply swapped the 2-pin bulb holder with the 3-pin holder. Interestingly enough, the 2-pin bulb holder also screwed into the US corner light - so I figured the 'hole' was the same. I'm thinking that there might be a difference in the bulb holder design between the different years of w123.

I could not use the 2-pin bulb holder without modifying the existing 3-pin plug, so it was just easier for me to swap the 3-pin bulb holder and reroute the running light feed over to the city light. It would be super easy to get the running light functionality back on the corner light if I decide I need it - just run a wire back to the 3rd terminal on the bulb holder.

The reason why I decided to go with the Euro configuration for lighting: I simply wanted my car to be more like a real Euro-market vehicle. With that said, I've been told by my friends that the turn signals are much more distinct and noticeable in this configuration. Perhaps this is the reason why my '95 Land Rover Discovery (US market) was wired up in a very similar fashion. Land Rover decided to add a separate sidemarker light on the bumper end, instead of putting the running light in the corner light assembly.

I do like having the city light function. It seems safer in the event that a headlight burns out, as oncoming traffic will still see the width of the vehicle. Kinda wish more cars in the US would come equipped with these city lights. Land Rover also elected to keep the city light for US models (yay!)

Hope this helps!

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Darren Asuncion
'81 300D Silver Blue metallic
'04 MINI Cooper S, Indi Blue w/ White roof
'94 Jeep Cherokee Sport, Flame Red
'95 Land Rover Discovery, Corallin Red