Taken from another forum:
The "reading lights" are on the left an fright side of my rear overhead dome light. The center dome light is not affected because it does not have its own separate switch. Also, my door panel bulbs are also not affected by the dimming issue because they also do not have their own separate on/off switches.
As discussed in other posts, here's what happens. All interior lights turn on full brightness and fade off when a door is opened and closed. This is GOOD. Unfortunately, when you click a switch to turn on any of the switch controlled bulbs, they turn on very dimly. This is because the led bulbs do not pull enough current to turn on full power from the light control "brain". I am not sure what this brain actually is (is t a Light Control a Module, is it the Body Control Module) so I will just refer to it as the "brain" for simplicity's sake.
The only way to wake up the brain was to leave one old incandescent style bulb in place in the interior that had its own switch. Some left the glove box light in place. I left my two reading lamps in place. To get the remaining LEDs to light up to full brightness, you had to first turn on the glove box bulb, or reach up behind you and tun on a reading light. Once the brain sensed the draw of ANY incandescent bulb switched on you could hear the brain "click" and all of your other LEDs would be fully bright.
Unfortunately, this brain would eventually go to sleep and if you wanted to use your map lights, visor lights or any other led switched lights, they would be super dim again until you opened your glove box or clicked on any other incandescent bulb which would then click the brain back into the awake mode to once again provide full brightness to your LEDs. This is a major PITA!
I am not exactly sure what causes the brain to go to sleep. I am not sure if it is time based or demand based. I do not seem to be able to clock a specific set time on how long it will stay awake. Some times, I can have my truck running for a few hours and it will still go into sleep mode.