LCD Brightness

Is there any way to adjust the LCD backlight on the TAZ5? I’d love to be able to dim it most of the time.

Yes

Or, rather, the contrast only I think via the clicky knob interface.

There might be a way to add it.

http://devel.lulzbot.com/TAZ/Guava/software/current/Marlin/Marlin/ultralcd.h

You could take a piece of auto window tint and stick it on the panel.