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Chevy 3500 dually

The latest problem is with my headlights. I lost the low beams. Running daytime lights work, and high beam lights come on but not the lovw beams. How to fix?
Thanks, Dave

Hey dmp
The most probable cause for your low beams is the light bulb itself. Many vehicles use dual fillament bulbs in the head lights. Durring low beams current runs through one of the fillaments, then when you switch on high beams they run through the second fillament in the bulb. When one fillament burns out it cuts current flow to only that wire. The second fillament will operate just fine. To diagnose pull one of bulbs and check so see if there is a black mark on the inside of the bulb or if one fillament is disconnected. Granted, the odds that both bulbs burned out at the same time are very low but its very easy to diagnose and its at least step #1.

best of luck with the repair, best wishes