Turn signal problem

There is a Chassis Node with three 21 pin plugs on the left frame rail or under the driver's side under the cab. The lights for front and rear run through the node. You really need a wiring diagram. The Node may be your problem, but the part is not cheap. About $600 - $1,000 used and $1,600 - $2,000 new. What happens when the four way flashers are on? Follow the tail light harness from the rear lights forward. There will be one connection between the taillight harness to the rear chassis harness which leads to the node. You can unplug the connection there and see what the lights do. Same with the plug at the node. If nothing changes then you ruled out any problems from the node back. Unplug the input connector at the node, try the signals and see what happens. Are the light signals ok on the dash?

 

Did you check your wires with a test light? Could be as simple as a broken ground or +

 

I had issues with my left side rear and mid side of cab turns on my 2016 Pete 389 Cottrell a few years ago. I found that those lights were on a separate fuse from the mirror and front turns. There is a junction box on the back side of the tractor near your hydraulic connections that Cottrell wired those and some trailer lights through. Take the catwalk off and you have easy access. My first thing I would do is run a new ground wire before I went any further.

 

I have had 2 issues with my turn signals on my Freightliner.
1. bad ground - lights would not blink in unison, blink slow, not blink at all.
2. turn signal relay - lites stop blinking, and then may blink, due to owner before me (2 years prior) installing LED turns signals. Found out LED bulbs need a “grounded relay”). Fixed the issue. Not sure if that will help any.

 

The fuse box was the one under the hood. If you get close to Indiana I have a shop that will fix your issues and they are very reasonable.