Aftermarket fog light wiring

[Master7122]

Is there anyway to wire aftermarket fog lights to the stock fog light switch? My Comanche didn't come with fog lights but I found a nice factory fog light switch that Id like to use

[ComancheKid45]

The harness should be there already, just have to dig out the plugs up front and behind the dash panel.

[Minuit]

You can use the switch with whatever kind of lights you want. It's just like any other switch. There should also be a plug under the dash (probably behind the switch panel on the left side of the steering wheel) that goes to the OEM fog light wiring.

 

You can also add factory fog lights by swapping out your front lighting harness for one from an 84-96 Cherokee or Comanche that had fog lights. No wiring work needed at all, just plug and play. If you don't want to use the OEM fog lights you could snip the plugs off or make an adapter. Probably takes less time than wiring up aftermarket lights, too. If you like a streamlined looking install that's the way to go IMO.

[Knucklehead97]

On my other MJ I used an aftermarket harness with a factory switch. Just had to crimp on female spade terminals and connect them to the factory switch.

[HOrnbrod]

Here's how I did it using the dash fog lamp switch and p/o the existing harness. This is for a 91; your wire colors may not be the same.

 

[schardein]

I've added fog lights to several XJs and one MJ over the years using the factory switch and panel.  The plug for the switch and the light bulb socket for the indicator light on the panel will be behind the dash.

 

For the front lighting harness, I have found differences in wiring that made it NOT a plug and play.  I don't remember the different years involved, but I did have to move the pins around in a junkyard sourced front harness that included factory fog light wiring, to make it work in my MJ.  If you have a basic understanding of vehicle electrical wiring, it wasn't a big deal.  You could even get a front light harness from a non originally fog equipped XJ/MJ and remove the pinned wires and re-insert them in your harness and "homebrew" your own setup like Don has shown above.

[Minuit]

 

For the front lighting harness, I have found differences in wiring that made it NOT a plug and play.  I don't remember the different years involved, but I did have to move the pins around in a junkyard sourced front harness that included factory fog light wiring, to make it work in my MJ.  If you have a basic understanding of vehicle electrical wiring, it wasn't a big deal.  You could even get a front light harness from a non originally fog equipped XJ/MJ and remove the pinned wires and re-insert them in your harness and "homebrew" your own setup like Don has shown above.

 

I took a look at the '94 FSM since that's the latest one I have, and the pinout for the front lighting connector is definitely different. Didn't know that before and I apologize for giving wrong information :oops: The '94 FSM I have mentions parking light and high beam relays on the front left radiator closure panel, which is confusing to me because I have never heard of an XJ having those. I can't find any other evidence that 94+ XJs have them, so I'm not sure if I trust that particular copy of the FSM.

 

The '91 and '90 FSMs agree with eachother. I don't have the '92 or '93 FSM it looks like the change occurred between '92 and '94 for sure, if I had to guess '94 assuming the manual I have is right. My fog lamp harness came from either a '92 or '93 and it was a perfect match. I did need to replace the connector on the harness since it was corroded but I didn't change the arrangement of the pins.

[HOrnbrod]

I like to make most all of my harnesses when I add stuff instead of using old wiring from a wreck. The OEM wiring was barely adequate at best, and the older it is the worse it gets. I made harnesses for the power mirrors, windows, trailer harness, the fogs, and others I've forgotten about always using higher gauge wire than the factory did and new connectors whenever possible.

 

EDIT: Someone here was redoing the entire factory wiring system on his rig awhile back, and it looked promising with some good ideas. Posted some good schematics that made good sense. Anyone remember who that was?

[Master7122]

Thank you everyone for the input/advice. I'm going to true and homebrew my wiring harness this weekend and see what I can do. Doesn't seem too hard to do

[Crash]

I used some chinexican harness off amazon, and just removed the switch from it and connected to a factory switch. I need to get a bulb to illuminate fog light symbol, but the small light in the switch illuminates when lights are turned on.

[MeanLemons]

I like to make most all of my harnesses when I add stuff instead of using old wiring from a wreck. The OEM wiring was barely adequate at best, and the older it is the worse it gets. I made harnesses for the power mirrors, windows, trailer harness, the fogs, and others I've forgotten about always using higher gauge wire than the factory did and new connectors whenever possible.

 

EDIT: Someone here was redoing the entire factory wiring system on his rig awhile back, and it looked promising with some good ideas. Posted some good schematics that made good sense. Anyone remember who that was?

I ll love to find that too.

[zetabird]

Here's how I did it using p/o the existing harness. This is for a 91; your wire colors may not be the same.:

 

wow that is exactly what i was looking for, it helps confirm how i wanted to do this, thanks

[robfg67]

On 1/11/2017 at 11:23 AM, HOrnbrod said:

Here's how I did it using the dash fog lamp switch and p/o the existing harness. This is for a 91; your wire colors may not be the same.

 

http://i.imgur.com/SLXI9TR.png

This diagram should be put in an electrical 101 book.

 

I followed it exactly and the fog lights lit up the first try with no debugging.

 

I cut the green with black tracer wire that comes from the fog light switch in the dash at the 10 pin connector and connected it to 86 on the relay.

 

Thanks

[schardein]

9 hours ago, robfg67 said:

This diagram should be put in an electrical 101 book.

 

I followed it exactly and the fog lights lit up the first try with no debugging.

 

I cut the green with black tracer wire that comes from the fog light switch in the dash at the 10 pin connector and connected it to 86 on the relay.

 

Thanks

If you used the factory connector for the dash switch, it is probably a green wire at the "B" (center) terminal on the switch.  That wire is only hot when the low beam headlights are on.  

I prefer to be able to use my fog (actually driving lamps) whenever I chose, by themselves, with low beams, or with high beams.  So I replaced that wire with one ran directly to the fuse block picking up ignition power; hot with the key on, so I can't accidentally leave them on and drain the battery.

That's how Don did it in his diagram- the switch being fed power from an ignition (key on hot) source.

[zomeizter]

My 'manche has the switch connector for the fogs right behind the switch cover of the cluster bezel, I gather the wiring goes out to the engine compartment and there should be another connector there which would be the one to mate to a fog lamps harness, correct? If so, does anyone have a pic of what that connector looks like and/or the whereabouts?

[schardein]

 

20 minutes ago, zomeizter said:

My 'manche has the switch connector for the fogs right behind the switch cover of the cluster bezel, I gather the wiring goes out to the engine compartment and there should be another connector there which would be the one to mate to a fog lamps harness, correct? If so, does anyone have a pic of what that connector looks like and/or the whereabouts?

The connector is on the driver side behind the airbox, it is the connector for the lights in the front header panel.  The wiring for the fog lights won't be there if it wasn't factory optioned.  You can grab a front harness from a similar year MJ/XJ that was fog equipped from the junkyard.  The wiring changed over the years as this thread states, so it helps if you have a basic understanding of electrical circuits, and you can re-pin a different harness to make it work.

EDIT: to say that it's fairly common to find the pins in that connector very corroded, causing problems with the front lighting.  It's a good idea to check yours, and check any junkyard one you get.  Take apart the connector and look at the pins.  I've seen them corroded away to nothing.

[zomeizter]

Thanks Schardein, EE here so I will find the connector and properly hack it

[gogmorgo]

Just to add because it hasn’t been done yet, if you’re actually running fog lights and you want them to be legal, they need to be wired to only work when the low beams are on. 
If you want legal auxiliary driving lights, they must only be able to be switched on when the high beams are on.

Not that anyone here has suggested doing so, but you also can’t just stick any old lights on and call them something, they also need to be properly designed to comply with standard beam patterns for the specific light. There’s also requirements for light placement on the vehicle, fogs go lower than the headlights and aux headlights are supposed to be more or less the same height as the primary headlights. 

Enforcement of lighting standards varies wildly between jurisdictions so there’s a lot of people out there who get away with a lot of things and some people get away with absolutely nothing. But regardless of jurusdiction, ultimately the legality of your lighting system is determined by federal regulations, FMVSS 108 in the US, CMVSS 108 in Canada is effectively the same. Whether it’s because of non-compliant lenses, mounting position, or wiring them to operate them independently from the respective primary headlight beam, any non-compliant lighting needs to be covered at all times to keep the vehicle legal for road use.