On all newer Ford models, LED cluster lighting is controlled by upper and lower MOSFET switches on the cluster board. The MOSFET on one side controls the duty cylce pulse that makes the LEDs look dimmer or brighter, and the MOSFET on the other side turns the entire circuit on or off.
On my 2007 Edge, I actually found the MOSFET that does the pulsing, and I shorted the drain and source pins as a test to keep the cluster bright. 2009 and newer E/M/Ts use a different cluster that keeps the LEDs lighted even when the headlamps/parking lamps are off, so to keep them on the bright setting, you'd need to disassemble the cluster, find the MOSFET that controls the dimming pulses, and short the drain and source pins. The only problem is that the cluster would stay on maximum brightness all the time. There's really no other way to do this, since the circuit that controls the pulsing is part of the "network" of modules that includes the instrument cluster.
If you don't know what I mean by pulsing, try this: at night, turn on your parking lamps and dim the cluster to minimum. Now look left and right of the cluster several times, very quickly. You'll actually see the entire cluster flashing on and off, like a strobe, and the pulsing properties will change as you increase or decrease the brightness. Since LED on-and-off times are in the milliseconds, it's easy to control their apparent brightness by pulsing them rather than increasing or decreasing their current (which is not always linear versus light output).
I'm not sure if this makes a difference, but I have the automatic climate control system on my 2010, which includes a sunlight sensor. Even with the headlamps on, the cluster and the message center do increase to full brightness (along with changing the factory nav screen day and night display settings) with any light brighter than dusk or dawn, and they're easily visible, even in direct sunlight.
