Actuate the controller and see if you've got 12VDC at the hitch connector pin. (It's the pin at the 5 o'clock position looking into the tow vehicle plug.) If so, it's not your controller but something on the trailer. The numbers dimming sounds like there's a short somewhere.
1988 Coleman Sequoia - popup (1987-2007)
2012 Roo19 - hybid (2012-2015)
2016 Mini Lite 2503S - tt (2015 - ???)
2011 Traverse LT, 3.6L, FWD
2009 Silverado Ext Cab, 5.3L, 4x4, 3.73
2016 Silverado 2500HD Dbl Cab, 6.0L 4x4, 4.10