Toomas

I have same problem with lights no working on 2020 2500hd with an additional problem, I get error messages to check left signal, then right signal, then brake lights and no trailer is attached. Working fine until last time I hooked up trailer, also when this happened my turn signals blink really fast

Have 2020 DenalI 2500 HD, have always had a problem with "trailer disconnected" warnings when pulling 5th wheel, but solved that problem by pushing 7 pin in further, so ok. Now though I disconnected my trailer and get same messages(and NO trailer is attached) and also blinkers are very fast. Any ideas?