While replacing my front turn signal light's (the entire assemblies) I noticed that when I turn on my running lights the front running lights come on, but once I turn on the headlights the running lights go out. This only happens on the front lights. The rear's work normally. To rule out the turn signal assemblies (both old and new) I checked for voltage with them removed. With only the running lights on, I have 12v. With the headlights on I have 0 voltage.
I suspect I have a bad headlight switch, but just wanted to see if anyone else has seen this or if you guys know of something else that might also cause this sort of issue?