Having issues w/ my gauge lights. At first, they would flicker off & on, now they are completely turned off. What could be the problem?

It's not an aftermarket gauge, it is the stock Roush gauges. I haven't taken it apart yet to see if there is something loose. Just thought I'd ask and see if anyone has run into this. Thanks for all the help guys.
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2005 Roush Mustang Sport - 5 Speed
DiabloSport Predator Tuner, Custom Dyno Tune, MMR CAI, BBK LT Headers (Ceramic Coated), BBK O/R X-Pipe, Roush O/R Exhaust, Granatelli UDP, MGW Short Throw Shifter
315rwhp/331rwtq
Upcoming Mods:
Gears, 4.10s