This 1999 F-150 4.6 XLT 4x4 first was having intermittent problems with the power windows. Fuse #110 in the engine fuse panel was checked and both the fuse and box contacts were cleaned but the correct operation of the windows was short lived. Recently the interior lamps and cargo lamps fail to operate, fuse #14 in the cabin fuse box was checked and found to be good. Has anyone encountered this problem?

 

Your issues are with different circuits and seem intermittent..
There are 4 different relays involved. 1, 2, 4, and 5 shown in your user manual.
You need to test with a voltmeter to see where power goes missing, not just check fuses.
The fuse block could have an issue supplying power to the fuses.
The GEM is involved on many of the functions that don't work.
Check for a windshield leak on the Gem.
Its located on the back side of the dash fuse panel.
Check the common ground behind the driver side kick panel for rust.
There could be more than one issue present to sort out.
Good luck.

 

Thanks Bluegrass, Will check these items out. I have noticed that the problem usually is present when first starting the engine and begin traveling. After a short time, usually around 15-20 minutes, at which point things go back to normal.