I'm not toung-in-cheek! I'm a former automotive mechanic with with 17 years professional experaince in addition to working on cars all my life.

READ VERY CLOSELY! A bad dimmer switch will cause headlight failure.

As for testing the dimmer switch, what is and is not hot at what click, check with craze because it's obviously ten times the automotive expert.

Craze:

<I purchased 2 new wire harnesses for my F-bird about 10 years ago and recently installed. Found 2 errors in production so far. One taillight socket installed backwards and, and one pair of wires crossed at a firewall connector. So I have had to do a repair two locations on my "new" harness to correct production mistakes>

If that isn't throwing parts at a problem, please explain what is.