My car: 2003 Sonata 67,000 miles v6 gl model

Recently, I noticed that my led lights that light up the fan speed around
the dial are out. The other knob which shows the blue going to red works
fine as well as the push button controls that are used to regulate the air
flow. Is this something easy to replace. I recently bought a garmin gps unit
and for the first time used the 12 volt outlet. Could this have fused the
led light out by chance. What steps should I do to find out why and how I
can correct the problem. It is very bothersome when your used to that knob
being lit at night and now its all dark!!

Thanks,

Jeff