Headlights inoperative - 2001 Yukon Denali

[Eagle1714]

My auto headlights are going off intermittently. When they are off, I cannot turn them on manually, the bright lights and running lights do not come on, but all other lights work. I checked the fuses and they are fine. I changed the headlight and running light relays under the hood but no change. Is there an electrical short causing this? Any help would be appreciated.

[bossier62guy]

From what you posted so far I'd be checking out that light switch first. You can rule out the BCM and the ambient light sensor since they won't work in manual. I've got wiring diagrams if it comes to troubleshooting wiring. Do you know how to use a meter?