trailer issue...help

Trailer lites work but no brake or signal...have reworked the connection to the 4wire flat still no brake/signal...suggestions??Thanks

Check and make sure your tow vehicle is putting out the brake and turn signal 12 volt. Unusual for both right and left brake light not to work, then I'd make sure your ground is good to both the tow vehicle and trailer. The ground wire is white in color.

Test the yellow and green wire on the truck plug for brake and turn signal with a $3 test light. They are the same thing. If no power there then that is your problem.

thanks guys

Also check the fuse.