Tips to Improve Voltage Drop from Trailer Connector to Back to the Rear Light Assemblies

Updated 12/09/2024 | Published 05/10/2019

Question:

I recently purchased an observation camera for my travel trailer. The camera company is telling me that the camera isn’t working because it’s not getting enough voltage. Apparently their cameras need 12.4 volts or greater in order to work properly. So, when I check the voltage at the factory installed “camera ready” location, it’s only getting 12.0 volts. The trailer is supposedly wired such that the camera power is tied to the running lights. I’ve confirmed that the nearby running lights, as well as those at the front of the trailer, are all getting the same 12.0-12.2 volts. I’ve also confirmed that the truck is putting out approximately 13.6-13.8 volts at the 7 pin trailer harness connection point. The truck is running with the headlights and running lights on. The problem exists whether the trailer is hitched tongue on ball or not. What am I missing? Where could the 1.5 volts be going?

asked by: John R

Expert Reply:

I'm not sure I totally believe that the problem is a lack of voltage. It's possible this is the case, but12 volts should easily power a camera designed for a standard 12 volt system. I would recommend taking the camera up near the vehicle battery and try powering the camera straight from the battery as this is where the voltage would be the highest. If the camera works here then it is voltage related. If not, then the camera is most likely defective.

Now the reason for the voltage loss is the resistance from the length of wire between the trailer connector and the rear of the vehicle. Only way to improve this would be to go with a heavier gauge wire here.

expert reply by: Jameson C

Steven S.

12/8/2024

I am getting a 1.5 drop at my plug today n at the 7pin plug in. I only have 10.5 volts at my rear marker lights but have a 2022 Chevy 3-4 and a 2016 redwood need hope. Just ordered a new heavy duty cable to help and to fix my what seems loose connection at my truck plug

Jameson C.

12/9/2024

@StevenS Some voltage drop is pretty normal but did you check this with the truck running or not running? If not running it will be higher once it is due to the alternator. That said, heavier gauge wire will help get rid of voltage drop.