Weird left blinker
 

I have a 2005 ZR2 Blazer and I took it off road and through some water today. Not long after, the left blinker started doing this thing. When the dash lights are on, the left blinker stays on when I turn it on. But when the dash lights are turned off, the blinker works like it should. Only problem is, the dash lights flash in sync with the blinker like it's on the same circuit. Already checked all the fuses and everything in the relay box, everything checks out. I've read this may be a ground issue? Anybody have any insight on this?