Rear fog light DIY

[amancuso]

***This info is still being fine tuned, but basically this is it.

BMW Z3 (2000-2002) 2.3, 2.8, 2.5i and 3.0i) Rear fog light retrofit. For 1996-1999 and all M models, you have to run 2 wires from the under-dash area to the tail lights.

In order to do this retrofit there are three stages
1. Cabin
2. Engine Bay
3. Trunk
I will explain each point below

1: Cabin

A) Remove under dash paneling, it is held in by two plastic twist and push pins.

B) Remove Driver’s side kick panel/dead pedal.

C) Locate Large Wire Harness at Firewall on the right side as if you were sitting in driver’s seat.
You may have to cut a zip tie or two and remove some black fabric tape to expose the bundle.
Once you have access to the wires look for a grey/violet wire and a grey/yellow wire. There will be 4 in total, two of each color combo. The purpose of these wires is to power the two (2) parking lights at the back of the vehicle on L and R sides. We are going to repurpose one on each side to carry the signal for the fog lamps.
Being that the wires are identical, you will have to either probe the wires or do as I did and just cut into one of each color set. At this point it doesn’t matter which you cut because if it is the wrong position it does not matter, it can be rectified in the trunk portion of the wiring. Once this is done turn on the parking lights to see which two of the four bulbs do not illuminate and make note of it. This is important because it will tell us which positions to rewire at each tail light, if any.

D) Use a thin flat blade screw driver to carefully pop out the fog lamp switch and it’s bezel.

E) Use an unraveled wire coat hanger to fish a wire and a string from the fog lamp button area to the area under the dash where you are working. I used a blue wire to connect to the fog lamps.

F) Splice the two wires you cut from the car’s wiring loom together with your freshly installed blue wire that is going up to the fog light switch.

G) At the other end of blue wire you already have (from the tail lamps) and crimp BMW part number 61 13 1 376 202 onto it.

H) Insert the blue wire into position number 1 on the fog light connector switch (Relocate existing wire to position 3 using BMW tool 83300495385. )

2: Engine Bay

A) Locate Fuse Box on LH side.

B) Unscrew 4 T10 screws holding fuse box together and lift up fusebox slightly and rotate it to the side so you can see underneath it.

C) Locate Fuse 17. In that fuse bank, remove all fuses. On underside of fusebox assembly, locate tab underneath the fuse bank you removed all the fuses from and push the fuse bank downward. Once you unseat the side by the tab, rest the assembly on the box and push downward on fuse bank to unseat it from the assembly. It won’t be easy, but be firm and apply some force and it will unseat.

D) Locate Relay K46 It should be a green relay. Remove this relay, and look under the assembly to find the tab for the relay connector. Push tab, and press the relay connector downwards.

E) Use your coat hanger from inside the cabin and push it through the bundle of wires at the firewall, once it pops out in the fuse box, tie a red wire to signify + power source and pull it through to the fuse box.

F) Inside the cabin take the other end of the red wire and crimp BMW part number 61 13 1 376 202 onto it then insert the wire into position number 2 on the fog light switch connector (Relocate existing wire to position 4 using BMW tool, part number 83300495385.)

G) From the fusebox area take the red wire you pulled through from the cabin and splice BMW part number 61 13 1 370 691 to it and insert it into F17 in the fuse bank.

H) Take one one (1) foot lengths of red wire and splice BMW part number 61 13 1 370 692 onto either end then insert one end into the center pin location of relay K46 connector, and the other end into the remaining connector for fuse F17. Reassemble fusebox. You are now done in the engine bay.

3: Trunk

A) Remove the covers for the tail lights

B) Unplug each tail light and separate the connector from the body nut.

C) Remove the three (3) 8mm nuts holding the tail lights to the body.

D) Remove tail lights from vehicle.

E) On a work bench or similar place tail light face down with the backside facing you, remove foam gasket, it just is held on with adhesive, and set aside.

F) Remove all bulb holders

G) Remove six (6) small brass colored screws

H) Remove Bulb holder wiring plate.

I) Use a small flathead screwdriver to relocate each wire to the desired destination. If the correct wires were cut, you would need to move the outermost grey/black wire to the position where the outermost black/red wire is located and vice versa.

J) Because our tail lights bulb holder wiring plate is manufactured differently, we need to space the newly purposed brake light further away from the lens. To do this you can use a small nut between the tail light assembly and the wiring plate, or you can place something on the tail light to bump it further up, I used a speed nut. You will also have to use two longer screws to make up for this.

K) Once you have reassembled the tail lights, you can reinstall them on the car.

[amancuso]

ROW Fog light switch:
fullsizeoutput_27ce by Al Mancuso, on Flickr

Fog lights on when tails modified to ROW spec:
Screen Shot 2020-05-03 at 10.41.25 AM by Al Mancuso, on Flickr

New Brake Light position when tails modified to ROW spec:
Screen Shot 2020-05-03 at 10.40.55 AM by Al Mancuso, on Flickr

[amancuso]

Cluster is modified as of 5/27/20 using the light filters from a Euro-cluster.

[KBH22102]

Very cool mod Al! So that cluster light is just a blank in North American cars? Did you have to install a bulb as well as the logo? How much cluster disassembly is required?

[amancuso]

Very cool mod Al! So that cluster light is just a blank in North American cars? Did you have to install a bulb as well as the logo? How much cluster disassembly is required?

Thanks! Yes it's a blank on US cars. You just remove 4 screws, and split the cluster in two. Once that is done, you just swap the filters over. The cluster I got was from an e36 diesel, which isn't really right as it was older and didn't have an EML light or an SES. I ordered a UK cluster from a 2.2i that should have SES and EML. As a stopgap measure I cut the filter from my US Spec and the EU diesel and glued them together. UK cluster should arrive in a few days. Oh, and yes, add a bulb!

Al.

[joelrg]

I don't want to come off as negative, just curious - What is the point of rear fog lights?

Joel

[KBH22102]

Increases your car's rearward visibility during poor weather conditions and is much less distracting that running with your hazard lights flashing.

[BimmerBreaker]

Its a good feature but sadly most US drivers just think you are driving around with your brake lights on

I may wire mine to have 4 brake lights instead of 2

[BladeRunner919]

We have them as standard in the UK, but I've never understood why manufacturers wouldn't just fit them worldwide.

[BimmerBreaker]

In the US it doesn't get foggy in the rear

[amancuso]

In the US it doesn't get foggy in the rear

LOL not true, try living in the northeast, where it's humid or damp, especially in New England.

[N1ck S]

This is a brilliant guide. Grateful thanks to Amancuso. I am just about to undertake this exercise on my 2000 Z3 2.3 roadster and just have a few questions of clarification:

The wiring arrangement seems to be taking the full power of the fog lights through the original BMW fog lamp switch rather than through a relay (as used on the European rear fog light installation). Does the standard BMW fog light switch have the rated capacity to be able to do this?

I will be purchasing a used BMW fog light switch as my Z3 is not fitted with one at present and so I assume the reference in item (F) above about "(Relocate existing wire to position 4 using BMW tool, part number 83300495385.)" is not aplicable to my situation. If this is correct do I still need tool 83300495385 for any other parts of the installation?

I assume that the cable to the gauge cluster shown on the added thumbnail is only relevant to the later enhancement of "using the light filters from a Euro-cluster"?

Any help, comments or feedback would be much appreciated.


Nick

[Cremaster]

Your hazard lights are not supposed to be used for a moving vehicle. They are for parked vehicles only.