Do you happen to have LED turn signals or brake lights? A similar thing happened to me when there was a short circuit inside one of my bulbs.

I've got a 2001 ranger with the 2.5 in it. The other day started having electrical problems. When my lights are on, my left turn signal stays lit but won't flash, my right signal will flash, and my brake lights stay lit bright. When my lights are off everything works as it should. I've already gone through all the grounds and cleaned and checked them all. Still nothing. Any ideas??? Thanks in advance