Warning Turn Signal On

It could be an earth problem, or as you guys call it a ground problem. Check that you have a proper ground on the plug that goes to the trailer. Sometimes it feeds backs trough the trun signals. Does the other lights on the trailer go weak insync with the turn signals when, you put the turn signal on. If so definately a ground issue.

 

Have look at the turn signals globes aswell. Front and rear, sometimes cororsion inside the holders can also cause this.

 

You can eliminate what its not,( you will be amazed at how much $$$ this will save you in diagnostic shop time).Does it do it all the time or come and go,(usually with bumps in the road) Does it happen only with lights on, or does it matter? You said you checked the pigtail, did you unplug it at the trailer and get back in the truck to see if it still glowed,if it does then it is in the truck some where. If its still glowing unplug it at the tractor end (if its not hard wired) and see if its still glowing, if it quits its the its the pigtail if not its in the truck. You said '07 Century that has Daytime Running Lights, does it stop glowing when you set the tractor brakes? If it does check the simplest first, set the trailer brakes and release the tractor brakes, I'm guessing the right DRL is out or very dim, check the bulb first if its good check the plug,if thats ok then follow the wires back til you find the bad spot. (any green or white fuzzy stuff in the wiring is BAD BAD BAD that means water is getting in)

 

BoyWonder, can you tell us/me what was the problem ? I am having the same issue in a 1999 Freightliner Century.

 

So what was it, goes off ever 5 minutes like clockwork?

 

So what was it. Goes off every 5 minutes like clockwork?