Chevrolet Repair Questions? Ask a Mechanic for Answers ASAP
The key fob receiver and the TPMS (tire pressure monitor system) run out of the same control box in the back of your suburban. If the shop accidentally cut the power to the control module it would do exactly as you describe. When they capped off the rear AC did they disable anything electrical back there as well? Maybe they unplugged it on accident?
Here is the location of the door lock receiver- you can check to make sure it's not unplugged, but more than that will require a scan tool to connect and see if it is communicating.