This may not be much help, but I'd recommend that you just give up the auto-on function, and turn it on or off yourself. Basis for recommendation: First, the auto-on in the TCH seems to me to be annoyingly hyperactive. By that, I mean that it will turn the lights on or off relatively quickly based upon changes in ambient lighting. In contrast, I once owned (though I now hesitate to admit it...) a 1998 Buick Regal GS (the supercharged tire-smoker) which had an auto-on feature that was very nicely buffered so that you didn't get quick changes based upon brief moments of light or dark (like bridge or short tunnel passages). My concern with HIDs would be that if you get a couple very quick on-off cycles, you may overheat and damage (or destroy) your HIDs.
As to the rest, I'll defer to the lighting experts who reside here. That said, from what I can "logic out" and infer from this car's "switchology", I'm afraid that what you're wanting to do will necessarily involve "neurosurgery" on the wiring harness -- a scary proposition -- instead of a simple and clean exchange of one component for another.
Good luck -- proceed with caution.
Linear Mode
