Driving Lights wiring question

I am wiring up two 100w driving lights. I would like to know if there is any problem if I splice into the auto shifter indicator light (you know, the indicator that tells you if you are in park, neutral, drive etc) for the 'power terminal' on the switch that will then send the signal to the relay (not for the relay power source obviously, but for the switch power). Also, 12 gauge wire should be fine for running both positive wires from the lights to the relay, right? I am using 12 gauge for everything because I have a bunch of it. That's OK right? Although the wires coming out of the driving lights are 16 gauge. Thanks.

You should be fine, splice into the power wire *before* it goes into the indicator lamp, and run that to your relay coil, then ground the other side of the coil. I don't know for sure, but I think the lamps are around 2-3 watts (167mA to 250mA @ 12V), and a relay coil will be around 50mA or less. The current will favor the lamp since it is lower resistance, but you should still be have enough current to pull the relay closed. You're tacking on way less than an amp to that circuit, so the wiring/fuse for illumination should be fine to handle it. If you were to splice into the line after it comes out of the indicator lamp, it would split the 12V between the lamp and the relay and you would find your lamp to be dim.

And I'm sure you already realized it, but with your regular headlamps off, the gear selector lamp won't be getting any power and you won't be able to use your driving lights. Obviously being lights you will probably use them with your regular headlamps, though. Good luck!

What about splicing into the cigarette lighter? That is where mine is and I have no problems.

as long as you're just splicing to go to the relay you're fine b/c the relay draws minimally. Don't ever splice a power line directly from the lights though or you'll be blowing fuses!

Even if your XJ/MJ didn't come with factory driving or fog lights, a lot of the wiring is there in the harness. This pertains to models through 1996, I don't know about newer models. The fog light switch connector is tucked up in the dash, and is used to trigger a relay you will have to add-in. The output from the fog light switch terminates on the 10-pin forward bulkhead connector on the drivers side, so why not use it? Here's how I wired up mine, hope it save you some time: