my 2011 santa fe developed this. When light switch is in either the auto or the off position all of the internal blue lights (ex dashboard, clock, power door locks, etc) blink when the blinker is turned on, they also dim when the brake pedel is pushed, when pedal is released they go back to normal brightness.
when the llight swich is either on the light setting or the parking light setting, everything is normal, they do not react like above.

 

Have you found the reason for this?
Is it fixed?
Did you check relays?
Was it the stalk switch?

 

have not located it.Now problem stopped before my scheduled appointment with dealer to run diagnostics. Need to have problem start up again and then get to dealer.

 

Have seen similar issue when the four way flasher is on
All the lights will flash or dim as the four way flashes
It turned out to be the battery's chassis ground
Corrosion, even though not visible, can cause high resistance
Which in turn can make for lots of annoying electrical failures

I would clean up all cable terminals on battery, alternator, starter
And clean up grounding points on battery and engine straps to chassis