I had a local shop install my electronic boost gauge and it works great. But now when I turn my headlights on all the OEM gauges and lights (radio, AC controls) dim but the OEM gauge cluster stays on the bright setting (does not dim). Was the wiring installed incorrectly? Is there a way to have all the factory gauge cluster and accessories dim again or is this something I'll have to live with?

Sounds like they wired something incorrectly.. I'd take it back.

Doesn't necessarily sound "incorrect", but they may not have tapped the right wire. I checked mine (Autometer installed by the dealership) and it doesn't dim either...