!997 C-3500 headlights

[transnet66]

When I turn my high beams on my low beams go off. Possible bad dimmer switch or headlight switch? Please advise.

 

[df2x4]

That's normal operation. All these trucks behaved that way from the factory. If you want to keep the low beams on with the high beams you'll need to do the "4-Hi" mod with a relay at a minimum.