When I'm driving in cold weather, the headlights (which turn on automatically) go out. I can turn them on with the manual switch. Which relay or fuse does controls this? Does anyone have a number or place to look to quicken my search?
The circuit is fairly complex. But you can probably narrow down your problem to the ambient light sensor on the dash. Or wiring from the body control module to the headlight switch.
I'd assume that the BCM provides 5v to the AL sensor and when it detects light it sends ground to the BCM or vice versa. So when it's cold the contacts in the sensor mistakenly sends a signal to the BCM to kill the lights.
You can try checking pins H (yellow/black) and G (light green/black) -AL sensor signal and return- on connector 2 of the BCM. As well as pin D (yellow) -output wire to the BCM- on connector 1 of the BCM.