Yeah you could do that actually. Most cars these days have their window switch lights linked to their dash lights. Some cars do it like i mentioned below.
But it really does depends on the car. My Ford Mondeo (Conture as its know in the states), the power window switch lights come on when in fact you switch the ignition on to accessory. Same with my 91 Toyota Soarer (Lexus SC400). So you could do it either way i think. It really is up to the individual.
Originally Posted by Rick Williams
I haven't opened the box for my power widow switches but from pictures I've seen they look identical to the ones I used in my '67 Mustang. Aren't they multi-pin? In other words, there's a pin to power the window and a separate pin to power the light. If so, for power to the backlight, use the same power source as you're using for the dash lights and the backlight on the fog and hazard switches. They'll come on only if you turn on your parking lights or headlights.