turn signals and stop light nightmare

[m&jtrans]

I have an 2002 gmc 3500 6.6l diesel auto trans SLE crew cab.

About a month ago the left turn signal stuck on, the right signal flashes like the 4ways are on, when anything is turned on (i.e.) 4ways either turn signal or the brake light the tail lights come on also.ive tried the multi function flasher no help, ive replaced some relays no help, ive looked the wiring,harness over no broken wires that i could find.

Whats next? A match?

I really need some help. Please

[RVJ]

Way back when, that meant a burn't blinker bulb. Might check them.

[m&jtrans]

They are new led with balancer built in