282 trim tab Reservoir location

On my '91 it's behind the rear facing access panel in the aft berth.
 
In my '94 Explorer, it's inside the cabin, in the starboard side storage well. Check your compression fittings while you're there, mine leaked and filled the forward bilge with hydraulic fluid.
 
I know on my 265 it is under my v berth, and on a freiends 282 it is located there as well, might check there. It will show on your owners manual and tell you the exact location, on newer models they located them where it is easier to get to and access for maintenance.
 
I have a 272 Sailfish. Mine is in the berth under the deck. 4 screws to remove the back wall.
 
Remove the plastic panel at the back of the extra bearth located at the bottom of the steps below the healm seats. The pump and reservoir are a single unit mounted in that space together with the waste storage tank.