1954 Buick
 

I was at a cruise night and saw a 1954 Buick Special, unrestored, new owner had only had it for a week.
He showed me the interior of the car, it was an V8/automatic, it had what appeared to be 2 dimmer switches, one were I would have expected and a second one closer to the brake pedal. Owner had no idea of what it did. Looked original, Car is in Canada.
Any know what the second “dimmer switch” does ?