If by dimmer wire, you mean the orange wire (also known as ''illumination''), 99% of the time, you don't. Otherwise, your brake lights or dash lights etc. could end up staying on. I believe that it's meant more for older older cars, but it's not necessary to hook it up. If that isn't what you meant, I apologize, if it is, I hope it helps!
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Potometer switch needs a constant power wire away from brakes ,lights and airbag circuit
If by dimmer wire, you mean the orange wire (also known as ''illumination''), 99% of the time, you don't. Otherwise, your brake lights or dash lights etc. could end up staying on. I believe that it's meant more for older older cars, but it's not necessary to hook it up. If that isn't what you meant, I apologize, if it is, I hope it helps!