Footwell Light installation, from scratch

By: Russ Caslis

Because it seems like a hot topic these days (and due to constant complaints from my fiance at night when she has to carry stuff by her feet), I decided to go about adding some foot-well lights to my M roadster. If you want to do the same, please read over these instructions before doing anything - there are several gotcha's that you may want to avoid.

Step 1 - parts

  1. 2 Z3 trunk lights - These come with the clear plastic pieces and bulbs. I used the trunk light piece, but you may want to consider using the entire dome light assembly. That would eliminate the need for the next two items.
  2. 2 12-volt 5 watt bulbs - The bulbs in the standard Z3 trunk lights were 10 watt bulbs, which were a little two bright and made a little more heat than I liked, so I replaced them with lower wattage bulbs. The new bulbs look like the same size, but they were smaller. I was able to bend the contacts in the light assembly to hold the new bulbs without any problems.
  3. 2 Radio Shack project boxes - I was concerned about wires getting burnt on the lights, so I decided to use the project boxes to cover the back side of the lights. Perhaps if I used the dome light assembly (which has a back) I wouldn't need this. The part number was 270-1801.
  4. Spade connectors - lots
  5. Wire - red & black 18 gauge
  6. Heat-shrink tubing - Just a little bigger than 18-gauge wire

Step 2 - disassembly

  • Side pillar coverings - These simply "pop" off. I would recommend using a screwdriver with the tip covered by a towel (to prevent marring the surface) and wedge it in the top, then pull down. These should come off with a nice "pop". Do both sides of the car.
  • Top pillar covering - The clear plastic around the dome lights gets scratched very easily, so please be careful (it's white plastic under the paint, so it really shows when it's marked up. The clear plastic pops off, try prying from the drivers side - that side is supposed to come off first. Then remove the light bulb assembly, it also pops out. Once again, be careful not to mark up the paint. Next, remove both visors, you will need a torx screwdriver. Then remove the one remaining torx screw that holds the top piece in place, it's behind where the light assembly was. Last, just pull up to remove the covering. You will need to detach the wiring plug that was under the passenger side pillar.
  • Passenger foot-well panels - Two panels need to be removed. First, take the bottom plastic piece out, it's held in by three plastic screws. After that, the panel should just pull forward and down. Next, remove the panel covering the speaker. It's held in by 1 plastic screw, then you push back on the panel so the lip comes out from under the covering under the door. Then the panel is free and just lifts out.
  • Driver foot-well panels - Two panels need to be removed here also. Remove the top plastic piece much the same way as the passenger side - remove the two plastic screws then pull forward then down. The only difference is that there are more clips holding it in place around the various pedals. Next, unscrew the handle for the hood. Then the side panel removes itself similar to the panel on the passenger side - one plastic screw and then push forward to remove the lip. Be extra careful here, since you are also removing the "dead pedal" on the floor (it's all attached - one piece).

Step 3 - Building it.

  • Grounding cables - You will need to create two cables for ground. Cut two pieces, one 25" long and another 15" long. Solder spade connectors on one end of both wires and cover with heat-shrink tubing. Uncover about 1/2 inch of wire on the other end of the wire.
  • Light switch - Disconnect the black wire and connector from the switch that controls the dome light (you may want to unwrap the electrical tape around the wire). Cut this wire near the switch, then cut a 6'2" long piece of red wire. Strip the ends of the black switch wire and the new red wire, wrap then together, solder on a spade connector and heat-shrink tube it. Connect the spade connector to the post on the switch. Take the other end of the red wire, and attach another piece of red wire 3'8" long, putting a spade connector on it (and solder and heat-shrink it). Now take the remaining end of the new red wire and attach a spade connector (and solder and heat- shrink it).


  • Cutting the panels - Cut a hole just big enough for the clear plastic piece to fit in. Be aware of what is just above the hole you are going to cut, you will need a good deal of space directly above the hole. Use these pictures as guides, but you probably want to move the holes even further back. And once again, be careful about placement, and double check that you will have space above the hole (it needs to have enough space for the project box above it). Also, you can make a hold bigger, but not smaller. Make the hold just big enough so that the clear plastic can hold itself in just based on pressure.


  • Cutting the project boxes - take the two project boxes and remove their tops. Now cut slits in the sides big enough for the two connectors from the clear plastic pieces to stick out the sides.

Step 5 - Final Assembly

  • Attach ground wires - In each footwell, near the speaker, there is a bolt with wires attached to it. Loosen both bolts and attach the non-spade connector end of the ground cables, then re-tighten the bolts.
  • Re-attach the top pillar cover - Put the cover back on in the reverse order from how it was removed. Just remember NOT to attach the connector along the passenger pillar yet. Also, run the new red wire along with the existing harness down the side of the compartment. You can push the red wire into the crevice by the door, the rubber molding will easily cover it all. Then re-attach the driver door pillar.
  • Run the red wire along the inside of the passenger footwell. Take the end of the cable and pass it though the center console so that it comes out the drivers side. You may want to tie something heavy to it, like a socket (from a socket wrench) to make it easier to grab.
  • Driver side - Hold the ground wire up and out of the way, then re-attach the speaker cover, doing the reverse of how it was removed. Remember to snake the black ground wire over the top of the panel. Now take the plastic lower panel, and place the clear plastic lighted piece through it, the project box over it, and attach the red and black wires to opposite terminals on the light. Put the plastic panel back into place, securing it with the plastic screws. Make sure that all the connection stay in place as you replace the panel.


  • Passenger side - Replace the speaker cover while snaking both the red wire and the black grounding wire over the cover. Now do the same thing as you did on the drivers side - put everything into place, attach the power and ground connections and secure everything.


  • Attach the wiring harness under the passenger door pillar and replace the plastic covering.

YOU NOW HAVE FOOT-WELL LIGHTS!

They are controlled in the same way as the dome light, and should make using the car at night easier.

That's it!