Forum Discussion
RoyB
Aug 29, 2014Explorer II
Not all trailers will have an OEM INVERTER installed. This is something the user adds to make 120VAC from the trailer 12VDC battery system.
It almost has to be some kind of RFI NOISE getting on your BATTERY CHARGE line between the Truck and the TRAILER. This would be the only WIRED CONNECTIONs between the Truck and Trailer. The connected batteries however on both ends really clean up things RFI wise...
POOR GROUNDS are another source of problems as well.
Here is a typical wiring BLOCK diagram for a 30AMP trailer system. Maybe will trip a thought or two...

Need to start tripping circuits I guess in an effort to pin-point source of problem. It will most likely totally amaze you when you find the source...
My 7-way cable terminates into an electrical box on the trailer side just under the trailer where the tongue frame is welded on and all of the trailer lights wiring etc is accomplished using large YELLOW twist-on connectors. The trailer wiring cable colors should be color for color connecting up the trailer side. Could be a easy place to have some frayed wiring or something like that touching something it shouldn't be touching...
got to start looking somewhere haha... All the information on this end is pure guessing...
Roy Ken
It almost has to be some kind of RFI NOISE getting on your BATTERY CHARGE line between the Truck and the TRAILER. This would be the only WIRED CONNECTIONs between the Truck and Trailer. The connected batteries however on both ends really clean up things RFI wise...
POOR GROUNDS are another source of problems as well.
Here is a typical wiring BLOCK diagram for a 30AMP trailer system. Maybe will trip a thought or two...

Need to start tripping circuits I guess in an effort to pin-point source of problem. It will most likely totally amaze you when you find the source...
My 7-way cable terminates into an electrical box on the trailer side just under the trailer where the tongue frame is welded on and all of the trailer lights wiring etc is accomplished using large YELLOW twist-on connectors. The trailer wiring cable colors should be color for color connecting up the trailer side. Could be a easy place to have some frayed wiring or something like that touching something it shouldn't be touching...
got to start looking somewhere haha... All the information on this end is pure guessing...
Roy Ken
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