Tech tip of the Day: WARNING, THIS IS A LITTLE WORDY AND NERDY. If you have questions please feel free to ask ; ). It has come up many times that the 12volt constant lead (pin 4) on your 7 pin connector does or sometimes does not charge the house batteries properly on an RV. The folk lore I see often times is that "it wont do it" or "it will only trickle charge it" Well for the the Big Three Trucks that is just not the case. Here are some things to check if yours is not charging properly. The T harness used to add a 7 pin in the bed for 5th wheels, often times gets installed without dielectric grease and will corrode causing a high resistance connection, (bad or weak connection) this will manifest it self with reduced current flow or if bad enough none at all. If you are having issues make sure the connectors are clean and add D-grease and it will improve current flow. Also if you are running dual batteries, cut out the grounds on both connectors and up the gauge wire and ground to the frame in the rear of the vehicle. this will also promote better current flow. for reference the power wire is usually Black and the ground is usually White. They should be 10 gauge, and if not upgrade to a better quality T harness that has good quality copper wire. Curt makes such a product. It is twice the price than the Amazon "most purchased" one but you get what you pay for in this case. Lastly verify that the wiring and connector on your RV is in good shape. We have all pull away from our RV and forgotten to unplug. if this has happened, check the connectors are not damaged in the plug and make sure the wiring is still un molested. if it is suspect replace the whip to your camper. Check the auto reset circuit breaker that all RV's should have between the end of the whip and wire going to the battery. it is usually located inside the J-Box the wires from the whip goes into. And lastly make sure the Ground wire is connected solid to the frame of the RV and that the Ground from the battery in the RV has a solid ground as well. Hope this info helps :-)

Posted by Joe Gross at 2022-08-17 18:19:14 UTC