I had the same problem once, and there is a simple fix.

If you open the startbox, you will find a small blue colored LCD Contrast potentiometer on one of the circuit boards. It is the only pot in the startbox.

Plug in the startbox, turn the transmitter and receiver on as if you were going to start the engine, and adjust the pot to get the desired display contrast/intensity.

Button the box back up, and you are all done.
This is covered in the owners manual, I believe.

Harley Condra
BVM REP
RAM REP