Low Voltage at trailer connector

[Nubbs]

Hey all,
It seems as though my trailer batteries are not charging while being towed behind my pickup. I measured the voltage between the +12 pin and the ground pin on the factory trailer plug receptacle mounted on the hitch. There was just under 12 volts with the engine running. Does this seem low, or is it normal? The voltage across the battery terminals is around 13.75 with the engine running. Any ideas for troubleshooting?

Thanks
Nubbs

[bobsherrie]

Voltage should be close to the same as the battery voltage with the engine running. I had the same issue and it was corrosion in the trailer plug where the wires plug in from the truck harness. Cleaned everything and all was good again.

[fordsforever73]

Originally Posted by bobsherrie

Voltage should be close to the same as the battery voltage with the engine running. I had the same issue and it was corrosion in the trailer plug where the wires plug in from the truck harness. Cleaned everything and all was good again.

Me too...I had only 2-3 volts charging battery for my camper. I ended up cutting the wire off about 2 or 3 inches back and replacing plug.

[Nubbs]

Thanks for the tips. I'll check it out.