I have some LED fixtures. They turn on when I use my architectural system preset stations on the wall, and possibly also when I use my saved presets / submasters on my lighting console. However, when I try to manually bring up the channels for the LEDs, they don't respond.
Explanation of Issue
Spaces that originally had incandescent fixtures who later installed LEDs instead often will use the existing dimmer rack/s (Sensor, Unison, etc) to provide power to the LEDs. Unless those circuits are configured to be always-on, this means the power to the LEDs can be remotely switched on and off with one or more particular DMX addresses.
These addresses are likely included in the saved presets in your architectural system and on your console. However, if you manually bring up only the channels that your LEDs are patched to, they won't respond, as they need to be powered on first.
You will need to figure out which addresses / channels control the power to your LEDs. If your channels are labeled in Patch, this may provide a clue.
Otherwise, choose a console submaster that brings up the LEDs, and look at its contents. The power channel is in there somewhere, so start testing each channel one at a time until you find the one that provides power to your LEDs. After they are powered on, you should be able to use their control channels to change their intensity, color, etc.