Hey guys,
I need some help here please. here's whats going on. My 02 tahoe has had a battery drain issue for a while now. initially it started with the battery going dead after a week or so of no driving. At the time my ignition was going bad so I thought there was a short in the ignition causing the battery issue. I just replaced the ignition but the drain is still there. Now this is the twist and the biggest clue, at least to me, even though thats not saying much is that whenever I turn the iginition on and the truck starts, the headlights automatically turn on as well, I know this because the dash lights and the PRND123 dim as they always have when the lights turn on. Before the issue, the headlights would only turn on at night by the ambient light sensors. Now since the headlights always turn on, no matter what, I have to manually turn them off by pressing the button on the light control switch twice on left side of the dash.

I have pulled all the circuit breaker's under the hood that control the headlights and lamps that i know of, but the dashlights still dim when I start the truck.
So what controls the dash lights, or the signal from the ambient light sensors to the dash.
BTW, I've replaced 1 ambient sensor (left one) cant reach right one without removing dash, and the headlight control switch.

I've also tried to trace a drain with a multimeter through the battery and the fuse box with no luck, but also not sure if I did it right to be honest.


Also one more question, if I remove the negative battery cable the battery should keep from getting drained right? or does that only apply if its a ground issue? The reason I ask is to remove the battery as an issue. its been tested before but I've had bad batteries came back ok on the test and were still bad. This battery has had a lot of jumps to it so I'm not sure if its part of the problem.

Thanks for any help guys.