Lockers, cabinets, whatever they are - they are the primary storage planned by the GMC interior designers. In order to remove the headliner or do any work that requires headliner removal, you must remove the cabinets. On our Palm Beach, the two front cabinets are different sizes. One is over the range and includes the vent hood. Over the dinette is a locker that is marginally useful for us. It's too short to put our GMC manuals in - except laying down, and the curve of the ceiling limits what else can be stowed.
The curbside locker runs from justbehind the passenger front seat, to nearly meeting the entry door. The cabinet is held in place by bolts that screw into insets placed in aluminum framing members. In the first picture you can see two bolts going into the wall, and barely visible are two bolts that go into the ceiling.
To remove a cabinet I first remove the electrical chase that hides the 12V wiring, and then remove the inside false bottom to expose the 12V connection. Disconnect the 12V wiring and check for any other non-structural connections that might have been made. I found additional wiring in one cabinet that was used to replace the original wiring that had been cut up. Next loosen all bolts one or two turns. This way you don't find out that there are frozen bolts when all other bolts have already been removed.
I always remove cabinets with a helper, so my procedure is geared towards that situation. Remove the outside top bolts and the inside wall bolts. This way the cabinet is still fully supported on the wall. Now have your helper take the weight off the bolts and remove the remaining top bolts. Remove the wall bolts and together lower the cabinet to the floor. The cabinets are fairly light but awkward, so it helps to have two people handling them.
You can see where the cabinet mounted over my dinette in two pictures. The first picture is towards thepassenger seat and the second towards the entry door. The ceiling and wall inserts for the bolts are clearly visible.
I don't plan to reinstall the cabinet over the dinette. Instead I'm building a custom set of cabinets on the floor that will hold our PC and other items. It's a little less storage than the cabinet, but the coach feels much bigger without the overhead.
If you're reinstalling the cabinets here's two suggestions:
1. replace the bolt with a stud that you screw into the ceiling. Then when you raise the cabinet it's a small matter to align the studs and install nuts. This should be much easier than trying to thread the bolts through the cabinet and into the inserts. Next install the wall bolts as normal.
2. using the original bolts - both you and your helper should have bolts in the bottom of the cabinet so that they are handy once the cabinet is in position. (Putting them in a pocket or other accessible place works too) Start by putting bolts into the outermost horizontal holes. Now you and your partner can lift the cabinet into position and guide the bolts into the inserts. Finger tighten them. Now have your helper hold the cabinet in postion. Insert a top bolt and finger tighten. Install the remaining bolts. Tighten all bolts beginning with the ceiling bolts.