I have my windscreen hooked to my lights. When they are on, it's on. Yes, it's bright with the top up and in the pitch dark, but it's fine once I start driving and I can see just fine out of my rear window...backing up is a bit tricky..hence, I'm having to replace my side mirror..that's another thread...

I have the switch to have a dimmer switch installed and/or have it hooked to my brake light so it will illuminate more brightly when the brakes are on. I love this illuminated windscreen...when the top is down and the lights are on, it's a true show stopper...I only have to wait 5 more months or so for that to happen...unless we get a heat wave in Seattle!