Wiring aftermarket fog lights into OEM switch?

My OEM fog lights on my 89 XJ were completely rotted so I took them off some time ago, but I would like to get a set of aftermarket fog lights for use in snow, which is coming Thursday. Since I pulled the old lights off, I would like to use my OEM switch to make the aftermarket ones turn on and off. Is there a write-up somewhere on how to make that work? I love my AutoPal 100w headlights, but the brightness has a downside when it's snowing heavily so I'd like to stick some yellow fogs under the bumper to help me out. Thanks.

What wattage lights? The factory harness itself is pretty small of a gauge. If its beyond stock wattage I would install a relay on that wiring, then run a heavier gauge wire from battery to relay to lights.

Yeah that's what I was thinking. Use the switch to just trigger the aftermarket fogs. No idea on wattage, I wasn't able to get them today. Since I have to wait, I might go for higher quality fogs instead of the cheap Walmart ones I was going to get. Any recommendations on some quality yet affordable fog lights? I'm looking for the yellow ones that cut "under" the fog and snow.

PIAA is what comes to mind.

Orange - This is the illumination wire, you can tap into another orange wire in the switch panel

Light Blue - This is the switch output, send this wire to the input wire of the foglight relay.

Violet - Connect to a fused 12v, or ignition source. If you'd like similar stock operation, you can connect this to the parking light output so that if you leave the switch on it will only get power when lights are on.

Black - Connect to a ground

Make sure you run a relay to your fog lights if you go this route, the oem switch CANNOT handle the current that aftermarket lights pull. I'd also run some 12g or at least 14g wire.

OK. Easy mod with a couple of options -

You can just plug the new lights to the original harness. Downside is that the wire is flimsy and there's a relay that interferes with your fogs when high beams are on.

Better mods is to install the new fogs on a new harness with better wires and relay, connect to the battery or PDC directly. You can take the activation wire to the switch and splice it to the existing wires just for activation. For switch illumination, you can borrow power from the neighbor switch - just splice there as well.

If using the harness that came with the kit, you are replacing two of the three wires going into the switch and extending them to the back of the factory switch.

The importance of a proper harness, solid ground and high quality relays cannot be stressed enough. Especially when using high wattage fog lights, like 85W and up. Good quality fogs are sold by PIAA (with good quality harness), IPF and Hella.