Lights, dashboard & head!lights

[Mitz]

While driving the other evening, with headlights switched 0N & dashboard lights lit up,  for no reason my dashboard lights suddenly went OUT.  Automatically, I assumed that I had somehow turned the dimmer dial all the way down, however,  such was not the case &  making sure the dimmer control was all the way up as bright as possible, I discovered that when I turn the headlight switch to OFF position the dash lights would LIGHT UP.  Turned the switch so headlights are ON the dash lights would go OUT again.  I checked this several times with same results.  Weird.  The dash lights should be lit up when headlights are On otherwise one can't read anything displayed on dashboard at night.

Any idea what would cause this &/or know how to correct the issue.

I bought my 2010 Edge SEL AWD V6 3.5L used Reconstructed.  My knowledge of auto mechanics is very limited especially with all the advanced systems & technology installed.  Unfortunately, I have to diagnose & try to fix things myself because i cannot afford to have a real mechanic or dealership perform the work & I know better then to allow some yayhoot, (who thiinks he can fix things at low cost), touch my car even if they do know more then I & their intentions are good.

Appreciate any n all suggestions & advice.