Both ideas have merit and I've experienced both. Since it's very rare for both bulbs to burn out at the same time, if it was me I'd start with the dimmer switch since it lives in a very inhospitable place and it consists of moving parts. It's common for the internal parts to corrode and/or wear out.

Last edited by Tiny; 03/31/2017 1:03 PM.

Save a life, adopt a senior shelter pet.
The three main causes of blindness: Cataracts, Politics, Religion.
Name your dog Naked so you can walk Naked in the park.