94 Dodge Ram 2500 with aluminum flatbed.

Had a late School Board meeting tonight. Noticed on my way home the left blinker indicator in the dash stayed on when using the blinker. OK, I have a lightbulb out...no, wait, it's a flatbed with the oval LED lights that "never" burn out, and the front blinker is lighting up. Looking around a little more, I see the third brake light on the rear of the cab is on. Pull in the garage, and I can see by the garage door that the rear brake lights are both on. Shut off the headlights and the blinkers work normally. So do the flashers. Turn on the parking lights and the brake lights come on, left blinker no worky right blinker work fine.

What is my problem? I don't think it's a ground, but I haven't ran a separate ground wire to check. I don't believe it can be the flasher, since the blinkers work fine wth the running lights off. I fear that I am going to have to replace the blinker("multi-function") switch.

Opinions?