Hey y'all, just bought an 03 1500 with the 5.7 and 147k miles from a buddy of mine. When I initially went to check the truck out, the AC button worked and I could switch the climate zone. Then when I went next to buy the truck, the battery had gone flat and I had to jump it. An airbag light, check engine light, abs and brake light were on the dash this time and the AC button, temp dial and zone dial were not working. I figured out that the CEL, ABS and brake light were for the rear diff speed sensor. However, on my way home with the new truck, all the dash lights turned off out of nowhere, my speedometer started working and I could suddenly use the HVAC control panel again. The next morning, back to square one. Any ideas? Seems like some bad wiring somewhere but I'm not sure where to look. Thanks! PFA

 

I would be checking that battery first with voltmeter. Static, cranking voltage. Then check running with everything turned on. Low voltage can cause lots of irregularly symptoms.

 

I'll check it out. I had the battery checked and it came out fine, checked with another battery just to be sure and same issues. But I can check with a multimeter too

 

The fact the battery went dead in 1 day, leads me down that path.

 

I should clarify, prior to the first time I went to look at it it'd been sitting for a year and had to be jumped, I ran it without driving it and I assume that didn't charge the battery enough. The next time I looked at it was a week later

 

A year? That battery went flat and sulfated. A jump and a run might have thrown a surface charge on it but it'll never hold a charge again.

Before you do any more diagnosing throw a new battery in it.

 

I've been driving it for a week now as is, battery is holding charge.

 

Think I would still have the battery load tested...... Just to be sure.