Troubleshooting RV Left Brake Light and Turn Signal Having Low Voltage

Question:

The left turn and brake connector in back of RV will supply enough power to work a test light but not enough power for a light bulb. The other parts of the 7 wire outlet are fine. I am at a loss to find the source of the problem. Please help.

asked by: Ben H

Expert Reply:

There are a few things that could be causing the low voltage issue you are having on the left turn signal and brake light circuit of your RV.

The first is that you have a weak ground that is not making a good connection. You will need to make sure that the grounds for that light, and the main ground on the tongue of the RV are secured to clean corrosion free metal. Weak grounds can cause all sorts of weird issues, including the issue you are describing.

Second is that there is damage to the wiring causing a voltage drop. Using your circuit tester like the # PTW2992 check the wire running from the left turn signal and brake light every few feet to see where the voltage drops. You will need to replace any damage sections of wire with # 16-1-1.

I included a link to a helpful article on wiring for you to take a look at.

expert reply by: Samuel C