Help!

[Brandon Watson]

My Yukon has been unlocking doors and lights turning on and off.Sometimes it starts sometimes it won't. I changed the mega fuse,and new oem ground cable. When I turn the key lights are on but it will not try to crank still.

 

[wjburken]

My Yukon has been unlocking doors and lights turning on and off.Sometimes it starts sometimes it won't. I changed the mega fuse,and new oem ground cable. When I turn the key lights are on but it will not try to crank still.

I would check the condition of your fuse box under the hood in the drivers side fender well. On my 2007 Silverado, I had an issue where the headlights wouldn’t turn off and had to pull the fuses, then one night the horn just randomly going off whenever the key was in the off position. Ended up having severe corrosion on the underside of the fuse block.

 

[intheburbs]

Locks cycling is an indicator of low voltage.

Check for loose battery cables and grounds.

Then check the alternator and battery. Auto parts stores will check them for free. They're not perfect, but it's sufficient in most cases.