I believe the wiring depends on if you have factory or aftermarket aux lamps.
The aftermarket lamps tend to have a plastic rocker switch, located at the base of one of the lamps on the support cross bar; where as the factory lamps have a small metal toggle switch on the back of one of the aux light housings.
Ideally, if you look at the base of the individual lamps, you should see a wire coming from the housing. Note the color and trace it back to the headlight bucket.
Inside the headlight bucket, the main
harness is wrapped in a loose plastic sheath. The aux light wire should be separate from the main harness and, based on the color of the one coming from under the individual lamp, be easily discernible.
The aftermarket lamps will likely have an inline universal splice inside the headlight bucket, tapping into the low beam circuit, making it easier to spot; and I believe the factory lamps have their own wire, with an inline male/female connector, inside a clear plastic waterproof sheath.
I also believe each aux lamp, whether factory or aftermarket, have a ground wire connected to the aux lamp housing using a rivet. Those rivets often work lose over time from all the vibration and tend to be a common point of failure. Be sure to check them.
If all else fails, using a 12v circuit tester lamp, work your way back from the individual aux lamp to their power source inside the bucket and go from there.
Hope this helps.
Best of luck.