Is your glove box light functional and does it have all the wires? There should be two Light Green/Yellow wires into the glove box light. One is the feed from fuse #8, and the other goes up to the map and vanity lights to feed them.
Tapped into this wire is the right courtesy light switch, which feeds the left switch and then to the dimmer.
My guess is you lost power from/to the glovebox light somehow and you are not feeding the map light normally and only when the dimmer switch is activated. I would test for power at the glovebox light and then from the LG/Y wire on the glovebox light up to the map light to see if you have continuty and constant power there.