2003 yukon with electrical gremlins

[03sltyukon]

I have an 03 Yukon that's giving me intermittent fits. Roughly two weeks ago I recharged the AC compressor due to having zero ac and found it to still not work when you turn the AC on but will freeze you out if you drop the temp down with only the fan on. The next day the alternator and battery went out on the truck. After replacing both and driving it for a few days its giving me a slue of intermittent lights and issues. The first of which is the 4wd selector switch bouncing around sometimes illuminated red in neutral and others in 4 low. On multiple occasions the truck went into what seemed to be limp mode when the selector switch was malfunctioning having almost zero power on the highway and holding high gear not down shifting at all. But if you turn it off and start it again it will shift fine and it hasn't done this in a week or so. It has also for one day only thrown a service 4WD but would go through 2 and 4 just fine. Most recently as of 20 minutes ago popped a service air bag light. Any help with any of these issues would be greatly appreciated.

 

[mizzouguy]

Certain years, the snowflake lit up means ac off and snowflake off means ac on. Sounds dumb but others can probably confirm. Not sure on 03. Id start by checking all of your connections to the battery and alternator. Check grounds, check power leads for looseness or corrosion. It seems like too much of a coincidence for all of these things to start happening after you replaced those two. Maybe also test new alternator you put in to make sure voltage reg is good.

 

[Eroracing]

Sounds like a possible floating ground issue! Check and make sure your chassis grounds are good and not loose!