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UselessPickles 07-20-2013 10:59 PM

Marker Light Turn Signal Mod - Cleaner Wiring
I did the marker light mod today so that my front fender marker light also acts as a turn signal. I have some details for an approach that will give you some very clean/simple wiring.

Refer to this thread for a full discussion of the mod itself:

And especially refer to this link if you want an explanation of how/why it works: Daniel Stern Lighting Consultancy and Supply

One thing I didn't like about various instructions/suggestions I found online was that they usually involved stringing a wire between the wire loom for the turn signal, and the wire loom for the marker light. Some instructions I've seen lead to the two wire looms being bridged by the wire in a way that prevents the wire looms from being removed for repairs in the future without cutting the wire, as well as having a single wire (and possibly it's connections) exposed in the wheel well area. I decided to follow the two looms up to where they merge into a single loom so that I have easy access to both wires right next to each other, with the end result looking indistinguishable from original factory wiring.

First, open the hood and remove the grill. I can add pictures/details for removing the grill if I get requests to do so. Or if someone can point me to a good forum thread with detailed pictures/instructions, then I'll link to it here.

The junction of the two wire looms you want is behind the headlight, so remove it (4 small torx screws). All following photos are from the driver's side headlight.

Pop the connector off the back of the headlight (one of those slide-the-red-tab-out-before-you-can-squeeze-and-pull types). This is what you should see with the headlight out of the way:

(green connector is headlight connector)

1) The wire loom junction. That's where you want to access/splice the wires.

2) Connector for the marker light. You need to disconnect the connector AND release the wire-loom-side connector from a plastic tab. To do so, gently pull the bottom of the connector body out towards you and slide the connector body down.

3) A pain-in-the-butt anchored zip-tie holding the turn signal wire loom. It's anchored with one of those barbed plastic plug things. With some patience and persistence, you can wiggle, pull, push from the back, and pop it free.

Also disconnect the yellow connector, and then you'll be able to pull the whole wire loom out like this:

1) Remove that electrical tape to expose the wires.

2) Marker light connector (loom-side).

3) That pain-in-the-but anchored zip tie, popped out.

4) Marker light connector (light-side).

5) Turn signal connector.

A closer look at the turn signal connector:

Black is ground. Middle wire is running/parking light. Last wire (as indicated by screwdriver) is the turn signal. This is the wire you want. Locate the same wire up at the wire loom junction:

And just to the left of of that, you can see the two wires for the marker light. The black (ground) wire from the marker light needs to be connected to the turn signal wire.

Here, you can see I have one of those wretched splice connectors (more on that later) sitting on the turn signal wire while I cut the black wire from the marker light:

And splice the black wire to the turn signal wire (the part of the black wire that is on the same side of the cut as the marker light connector).

And wrap it back up with electrical tape:

Simple, clean, doesn't require any additional wire, and doesn't look at all different than original :). Now just put it all back together (reverse what you did to take it apart), and do the other side the same way.

Now about that plastic splice connector: I actually prefer to strip away insulation, solder the connection, and seal the connection with liquid electrical tape. This should create the cleanest, most professional, and most weather-proof result. Just be sure that the soldered connection is in a place that is not going to flex or vibrate against something hard, because soldered connections can eventually break if stressed (solder is brittle). I actually plan to re-do these connections this way soon.

I had no power at the house and was bored. I just used the splice connectors that I had sitting around so I could do something productive. If you're not comfortable with stripping insulation and soldering, then a weather-proof splice connector wrapped well in electrical tape should be just fine as well.

Lusus_Naturae 07-21-2013 01:28 AM

Nice write up, I like how it's a cleaner design too, I'm always picky about that myself.

UselessPickles 07-22-2013 09:03 PM

I couldn't stand having those splice connectors any longer, so I soldered it up properly today:

And coated it with liquid electrical tape for a weather-proof connection:

Also, here's some details on removing the grill:

I couldn't find any way to edit the original post to refer to the grill removal thread :(

mikedboyd 01-12-2014 02:47 PM

I just did the 2-wire mod (just cut the existing wires to the marker light and merge them in with the turn signal wiring). quick and easy and seems to work as advertised.

xnavy8or 09-27-2014 02:10 PM

Great on 2015 JKU

BareBones13 09-28-2014 01:45 PM

I did this mod today as well and it worked without a hitch. I was adding a mesh grill backing so figured I should do them both at the same time, along with removing those orange side markers for clear ones.

GroovyGeek 09-28-2014 02:02 PM

Great writeup with useful detail to keep dummies (like me) from getting themselves in trouble. I do have to ask whether the alleged safety benefit is really there? Sure, it can't hurt, but does it help to be worth one hour of my time? Oh wait, I spray painted the damn muffler, I have lots of low value time 😊

One more serious question: this seems to wire the side markers in parallel with the turn signals, which likely halves the load resistance. Any concerns about fuses or other ancillary stress to the drive circuit?

James22 10-31-2014 03:14 PM

Will this mod work on a 2004 TJ?

UselessPickles 10-31-2014 07:30 PM


Originally Posted by GroovyGeek (Post 13720674)
One more serious question: this seems to wire the side markers in parallel with the turn signals, which likely halves the load resistance. Any concerns about fuses or other ancillary stress to the drive circuit?

I haven't had any issues yet, and I haven't heard of anyone else with this mod having issues.

Don't know about the 2004 TJ. I would guess it would work, but you're on your own identifying which wires to work with.

Notar1 02-17-2015 11:47 PM

Great write up made it easy to do this mod today in under a half hour. I soldered the wires, used liquid electric tape, then once it dried covered it with normal electric tape to be safe. Like how the lights wig wag when the headlights are on.

hkryan 03-15-2015 01:26 PM

Wow, nice and clean! Does the mod done per these instructions result in alternating blinking of the two lights or blinking at the same time?


Originally Posted by Notar1 (Post 17050314)
Like how the lights wig wag when the headlights are on.

"Wig wag"?

UselessPickles 03-15-2015 01:48 PM

Depends on whether the parking lights are on or not.

Parking lights off: marker light blinks with turn signal.
Parking lights on: marker light blinks opposite of turn signal.

The marker light still functions as a parking light with this mod.

The "wig wag" was a description of how the marker light and turn signal blink in an alternating fashion when the headlights (more specifically, the parking lights) are on.

2013 Moab 03-15-2015 02:00 PM

Notar let me take a wild guess and say you know a little something about airfield lighting, namely elevated guard bar lights...AKA wig wags.

Oh and OP glad you changed out those suit case splices, they are a failure waiting to happen... nice write-up.

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