I messed up!
 

Shorted out something with my interior lights (map and puddle lights) and now they refuse to work when the front doors were opened. I noticed fuse #9 blew but replacing it did not solve this issue but it got the radio working again. Map lights worked manually from the switch but not when the doors were opened. Noticed something that #9 fuse controls called a relay comfort security term 88. Did I short this out?

Messed Up!
 

Got out the multimeter to see what I blew up!

Seems it was a relay or a ground related issue! I rewired the negative ground system and got everything to work again including the footwell lights! Happy now!

I was not aware that W124s came with footwell lighting. Where are the fixtures located?

Wow. Footwell lights? :D

Ditto on the "Wow" -- where are these footwell lights?

footwell lights
 

I put the footwell lights in myself. LED strips that turn on when the doors are opened and turn off when closed.

Ahh. You had us for a moment. I went and scoured the underdash of my 91 :D

OOPS!
 

Did not mean to mislead anyone!

Several years ago I had my instrument cluster out and saw a constant hot lead the clock/cluster was plugged into (#9 fuse). I tapped that connection to drop a wire down to some LEDS I placed under the dash for the footwells. The negative connections went to one of the front door switches so they operated when the front doors opened and closed. I chose a yellow color to accent the saddle interior to give it a rich bright looking feeling.

I added footwell lighting to my 2005 Acura TL and will soon make it a mod on my 2011 Hyundai Elantra.