I have an 05 Avalanche z71, I tried starting it Sunday after driving it around Saturday with no problems and it wouldn't start. I thought it might just be the battery so I jumped it but nothing on the instrument panel came on expect for the battery and abs light, the windows and locks didn't work, the ac didn't turn on (even though the blower did) but I could still drive it down the street with no other problems. then I tried just turning the key and the instrument panel worked but the windows and locks still did not, but when I turned the engine on the panel went dark again with no battery or abs lights on that time.

fast forward to today, now I can't get the engine to stay on, I checked the fuses and couldn't find any blown and there's 8v still on the battery. could a bad alternator cause all of this to happen or could it be the ignition switch? I am a novice at this stuff but I've been able to fix alternator and starter problems in the past but I have no clue what to do now and money is kind of tight right now to see the dealer.

 

I'd suspect ignition switch

 

If you hear faint clicking when you turn the key, it's probably a bad alternator (Battery running the truck). If so, the battery is probably bad now too.