Fouros found this and posted a thread on
using it with his factory bar. Now granted he was installing a factory bar but I *think* it might be doable with other setups. Here is a portion of the wiring diagram for the BCM (body control module):
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Notice the 'Lightbar switch sense' connection. It is located in the connector that Fouros found behind the trim piece on the dash :
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Now if that connection in the BCM is looking for a 12v signal you might be able to tap a wire off of the power wire that goes from your switch to the lights and connect it to the brown/yellow wire and it would illuminate the lamp in the instrument cluster. If it is looking for a 5v signal you'd need to add a resistor in series with the 12v tap to lower the voltage to 5v so you don't fry the BCM. If there is someone with a factory bar that could measure the voltage coming off that wire it would help.
Alternately (and possibly more likely to succeed) you could get a factory switch for the light bar and connect your power leads to the connector in the 'A' pillar that Fouros found. Just a couple of possibilities to consider...
Just remember that if you follow what I have outlined you do so at risk - I'm a shade-tree electrcian so if you fry your BCM and your Jeep goes TU don't come cryin' to me
