I’m sorry about your arthritis. My husband and I have it too. This cold winter isn’t helping.
After reading your post I wasn’t entirely sure of myself. You made me go look it up, so I thank you for that. I like learning.
Automobile lights use Relays. “Most headlight switches use an electromechanical device called a relay to control the lights.”
Read more: http://www.ehow.com/how-does_5040978_headlight-switch-work.html#ixzz2tbrix7rD
The term dimmer = variable-voltage device.
http://en.wikipedia.org/wiki/Dimmer
The term dimmer tends to be associated with full range ‘dimming’. No harm done.
I hope we all have an early spring.
I hadn’t given the switches much thought.
Hope it warms up for you soon. It’s very soggy here with melting snow.