Oh - what a good question.

I turned them to both park positions the other night. They stayed on! But I didn't try to dim them. I'll try that in a few hours when the sun goes down. It's just too bright outside right now to see if they're on and/or off.

FYI - I had the rheostat replaced about 5000 miles ago and everything was working fine for quite a while after that. However, the car (and therefore the light switch) has about 200K and a couple decades. That's a lot of use.

Let's see what happens after dark.