Troubleshooting Turn Signals Not Working on a 4-Pole Setup

Question:

Everything works but turn signals. All running lights work. I have two trailer whites to one truck white. I have one green to one green. I have one yellow to one yellow and two trailer browns to one truck brown. All running lights work, no turn signals. HELP!!!!!!

asked by: David C

Expert Reply:

The first 2 things that you want to check when experiencing wiring problems is all of your grounds and the connectors on both your tow vehicle and trailer. You will want to make sure that the grounds are secure and have a metal-to-metal contact. Sometimes even some paint can cause lighting issues. To replace a damaged connector on your trailer you will need part # HM38138; for your tow vehicle you can use part # C58044.

If all of that looks good then you will want to test the wiring on your truck and your trailer separately to find out which one i causing the issue. You will want to use a Circuit Tester # PTW2979 to test the various light functions on the connector on your truck. To test the lighting on your trailer you will want to hook it up to a separate 12V power source (different vehicle or a 12V battery).

After testing the functions if any of them did not work correctly, either on your tow vehicle or your trailer, then you will want to physically inspect the wires for any places where it has exposed wiring, is damaged, corroded, or even bent. You can replace any sections with 16 Gauge Wire # 16-1-1 and Butt Connectors # DW05744-5.

If everything is testing good and looks okay then you will want to take both your tow vehicle and your trailer in to a qualified mechanic who can physically inspect your setup.