(NOTE: I am not an electrician. I am familiar with basic wiring, having done simple projects for about 30 years. If you are not entirely comfortable doing such a project, please hire a licensed electrician who can easily do it for you, or just change out the entire fixture.)
The light fixture in my closet was under-powered so much that I couldn’t tell the colors of the shirts. I removed the glass cover and discovered that it was using orange-colored compact fluorescent bulbs with an odd base I hadn’t used before (GX24Q-2).
I searched online to see if there were LED lights that used this base, and found that while there were some, there were also adapter bases made to allow a standard bulb to be used. I purchased 6 off of Amazon and looked at the wiring description which wasn’t a lot of help.
It said to remove the fluorescent ballast entirely, but leave the wires attached to the GX24Q-2 sockets. On each socket there are 4 wires, 2 wires will be unused, 1 will be attached to the 120V white neutral wire and 1 will be attached to the 120V black hot wire.
I shut off power to the fixture at the breaker to prevent accidental shock. I removed the fixture from the ceiling and unscrewed the 3 wire-nuts holding the fixture to the house wiring (Ground, Hot, Neutral).
I used my multimeter to test which of the pins on the new adapters went to the screw socket and which went to the base contact. The side of the screw socket will be connected to the white neutral, and the base contact will connect to the black hot.
I found that 2 of the pins on the adapter were not connected (these correspond to the 2 unused wires), and then labeled the 2 remaining pins either B or W for Black or White. I also labeled the sockets attached to the light fixture so I could easily match them. (I’m not sure that it really matters for a bulb, but since I’m not sure, better to just err on the side of caution).
I used a marker to put a dot on each wire that went to either the B corner or the W corner. The other two wires I bent down and attached a wire-nut to keep them from touching anything electrical. I arbitrarily decided to make the yellow wires attach to Black 120V and the others to attach to the White 120V.
I used wire-nuts to attach the colored wires to the house wires. I turned on the power again and tested the lights which worked perfectly. I reattached the fixture to the ceiling.
All in all, the directions that came with the adapters left a lot out. It would probably have been easier to just get a new fixture, but it was a lot cheaper to do it this way. As I said at the beginning, if this is beyond your skill and understanding, please do not attempt to do it yourself. Hire a licensed electrician to do the work.