Just bought a used 2010 silverado 2500 LTZ package. I think it has the power folding mirror option. I have the two buttons on the armrest, and code DL3 on the service parts id tag. Never had this option before so I'm not positive how it works, but I tried twelve ways from Sunday, buttons by themselves, activating the side selector first, truck off, running, etc. and I get nothing. Even tried it with the remote fob, I saw some later years use the lock button, but no movement, no motor sound from either button. I did notice that when I hit the right folding button with the truck shut off, the right selector button above it lit up. Regular left/right/up/down adjusters and side selector work fine. Any ideas? It would be appreciated. Pic of control is attached.

 

See the owner's manual for Folding Mirrors in the Keys, Doors, and Windows section. The MyChevrolet app has your owner's manual as well. If the buttons are not working, I'd check the service manual for repair troubleshooting the switches, wiring, and mirrors. Do you hear any clicking or popping noises? Have they been folded or unfolded manually?