ALL trailer lights flash when 4-ways or turn signals are turned on: How to fix?

Noce illustration!

 

You forgot about the 1.21 gigawatts needed to power the flux capacitor that sends the electrical current to the light's, which can be achieved by reaching 88 m.p.h.

 

Barcode, great explanation. I knew what you were talking about without the picture, because I've had it happen, but I never would have been able to explain it with words. Top notch.

 

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i've been under my trailer adjust brakes and it's not wired that way.. it has one green cable running the entire length of the trailer and about 10' from the rear of the trailer it has two plugs that join into a splicer (for the left and right turn signals/markers), but the main cable runs to the back where it only has one ground. think i got boo boo'd on.

 

The trailer ground circuit needs to run through the pigtail to the tractor, running the ground through the fifth wheel or hitch is going to be problematic.
If the ground is interrupted, the voltage will find its way to ground by trying to backfeed through the rest of the lighting system.
If you are waiting for the fifthwheel to 'set' for your lights to work, you need to have the pigtail ground circuit repaired.
All of the lights should work properly even if the truck and trailer were separated.
The diagrams posted by lilillill are very good.

 

I realize this is a very old thread but I am having a similiar issue. I started the trailer wiring without having my truck connected and used one open circuit with a spare battery to light it up as I went to make sure all was good.
I then backed my truck all of the way under the trailer and tested using the truck and everything worked as it should. I wasn’t quite finished and had to unhook from the trailer. Finished the wiring and backed truck close enough to connect the lights, but I didn’t back all of the way under the trailer. When lights were connected the lights came on the trailer without even turning anything on. Turn signals worked but were also dimming the chicken lights. When I apply the brake the chicken lights turn off and then come back on when I let off of the brake.
So my question is do I need to be fully under the trailer for the lights to work as they should? Perhaps the ground is not complete without this?

 

For what it is worth I figured it out this morning. It was a ground issue