Pete 579 no left turn signal on trailer

Have you tried moving the plug where it plugs into the trailer? Try lifting it up, put paper or a plastic zip tie in the socket and plug it back in. If that doesn't work, check if there is power to the light.

 

Ok, have you checked the socket that the cord plugs into on the back of your tractor. I had a similar issue with that on my truck. Had no running lights on the trailer. Turned out the socket was bad.

 

I doubt it. Do you 4 way flashers work?

 

Ok. She if the back of the socket on the back of your truck is getting power when the turn signal is on.

 

Yes. Where the wire going into the back of the scoket. Use your test light and it should blink.