Troubleshooting Rear Running Lights not Working on Catering Trailer

Updated 01/29/2018 | Published 01/28/2018

Products Featured in This Question

16 Gauge Primary Wire - Black - Per Foot

(60)

$1.14

Deka Heat Shrink Butt Connector - 16-14 Gauge - Nylon Insulation - Blue - Qty 5

(1054)

$7.08

Question:

The rear running lights are not working on our catering trailer however every other light is....i have connected another trailer to my l200 so I know its not the vehicle as all lights worked so the problem is on our trailer...the whole trailer was rewired less than 6 months ago so cant understand what the problem is....is has been sat over winter so Im wondering is it just corrosion. The 7 pin plug did look rusty inside so I cleaned it all and still no running lights.....any ideas to the problem

asked by: Anthony C

Expert Reply:

You are definitely on the right train of thought. Wiring issues like the running lights not working is typically the results of some damaged wiring or a bad ground.

If you wanted to test your trailer you can take a 12V battery, like what is in your vehicle, and ground the Negative terminal while using the Positive terminal to test the pin in the 1 o'clock position on your trailer side 7-Way (see attached picture). If your running lights do not active when running this test then you definitely know that the problem is your trailer.

The next thing to do, since you already cleaned out the 7-Way, is to check all of the grounds on your trailer. Make sure they are clean and connected to a bare metal surface. Even some paint can cause issues.

Once that is done, if you are still having problems then you will want to check the wiring on your trailer. Looks for any places where the wires are bent, damaged, corroded, or exposed and replace. If it is on the running lights circuit you will want to use 16 Gauge Wire # 16-1-1 and Butt Connectors # DW05744-5.

If you are still having trouble after that, let me know and I can help you troubleshoot further.

expert reply by: Jon G