tobyw

'99 WITHOUT factory fog lights... The PDC does NOT have receptacles for the relay or fuse that power factory fogs, just empty slots, and the light blue wire that is supposed to power the OEM fog lights is NOT present at the harness connector by the PCM on the driver fender. So, where does the factory switch harness terminate? I have verified the orange wire on the pigtail does indeed have power for illumination and the black is grounded, but that's it... I'd like to use as much of the OEM wiring as possible for a clean install, but I can't determine where the factory wiring goes once it's in the dash loom. Any help would be greatly appreciated!!

Dunkelstar

I'm interested in this as well, as I'm doing the same on a 1998 and would like to use an OEM fog switch and as much of the factory wire harness as possible.

What fog lights are you going to use? I was thinking of a pair of Hella 550's, but wasn't sure if they would fit in the existing bumper cutouts.

tobyw

I'm actually going to use a pair of OEM TJ fog lights mounted above the bumper. Not really using them for a fog light, more of a switch-activated DRL...

GibsonSG

If this helps, if it has the plug behind the bezel, there are 4 wires: purple, blue, orange and black. Purple is power in, blue is power out, black is the ground and orange is the illumination for the switch. The only relay that would be in the PDC for factory fog lamps is one that kills them for the high beams. There is not, NOT, a relay for the fog lamps themselves. All power in the factory system runs thru the swith(purple/blue wires). Big time engineering brain fart. The factory switch handles all the current, and the most common reason why factory fog lamps dont work, the switch eventually fries. Besides the point. I would locate that purple wire, pretty sure they wouldn't just throw a bunch of different harnesses in depending on vehicle, so it should be there and thats your power for fog lamps.
The switch/current issue I remedied by installing a relay I got at auto zone, Duralast part # 19273.

tobyw

Good info, and understood on the relay vs. switch. However, there is also a fuse for the factory fogs in the PDC, for which I have no wiring receptacles, and apparenlty power runs through that fuse to the switch because my purple wire is dead... So, if I could find the starting point of that purple wire and the termination point of the blue one, I'd be in business!!

tobyw

OK, I answered my own question and I'll post what I found for future search purposes in hopes that it may help someone else out later...

The factory fog light switch has a violet wire that acts as incoming power, and that wire originates in the PDC and comes through the firewall to the driver footwell area, landing in a block connector known as C100. Very specifically, C100 pin location A5.

Similarly, the factory fog light swtich has a light blue wire that carries power from the switch out to the fog lights, and this is routed through block C100 in the driver footwell area; C100 pin location A4. Ultimately, this light blue wire is connected through C100, out the firewall, and up to connector C106, located behind the driver headlight.

Now, what I found is that the chassis-side of connector C100 did NOT have any recepticles for pins A4 or A5, but the dash-side of the connector did, and those wires run in the loom to the fog light switch. So, in my case, all I need to do is unpin the wires from A4 and A5 (or snip them off), and make the appropriate power in and power out connections to these two wires to have a functional fog light switch that uses as much of my factory wiring as possible. I plan to use a relay to power the lights, so unlike the factory wiring, my light blue wire will not run directly to the lights but instead it will simply trigger a relay that will handle the amperage draw of the lights.

GibsonSG

You wont be sorry. The difference in the amount of heat generated at the switch is very noticable when the lights are run thru a relay

I think that Duralast relay put me back 14 bux

I also got a pair of brand new factory replacement fog lamps off ebay for $67 shipped

salad

Sounds like you had fun! Interesting about C100. Are you saying the wires were present but the receptacles weren't on the chassis-side?

Also, wiring diagram here: https://www.cherokeeforum.com/f2/199...9/#post2217876

tobyw

That is the wiring diagram I followed, and I also found some schematics that showed the connector locations. Electrical work is NOT my strong suit, so having a picture/drawing was extremely helpful to me... And yes, the C100 connector had the wiring/pins on the switch side, but nothing on the chassis side. So the wires ran from the switch over to C100, and that's it. Just last night I snipped the wires out of C100 and soldered on my extentions, and today I'm looking around town for a suitable grommet to run the wires through the firewall.

salad

Ahh so there was nothing in the chassis-side harness AT ALL. Well... I guess I've got grommetting to look forward to, too. lol

1991Jeep_Man

Sorry to thread jack, but the blue and purple wires you mentioned.. Are these the input and output wires for the low beams through the headlight switch? Been trying to figure out the correct wire to tap into for signal to my home made fog light harness to the relay.

tobyw

Negative... According to the wiring diagram, these are "dedicated" wires just for the fog light switch itself. I believe the wires you are talking about are somehow linked from the headlight switch to the PDC and ultimately the fog light relay, because in stock form the fog light relay only gets power through the headlight circuit or something wierd like that?

JZENKER

So the connector behind the grill which has only two wires is simply power and ground? I should connect both fog lights to the same power wire and ground?

Wiring not my strong suit either.

kennzz05

heres the basic setup, however this uses none of the factory wiring

sorry i tried to post only one of those pics but it wouldnt work use the one on the top row all the way to the left

http://www.google.com/search?q=how+t...w=1241&bih=584

if you tap powerfrom the cigarette lighter (the one that goes off with the key) for the power to the switch than the lights will go off when you turn off the truck and could function as daytime running lights if you wanted

JZENKER

LOL! I opened your link first w/o reading your post, I thought it was April 1st for a second. Thanks. I'm going to try to connect them via the current factory set up and if that doesn't work I'll try your set up. Appreciate the intel!