How does a split charge relay work on a towing vehicle?
How does a split charge relay work on a towing vehicle? Split charge relays or tandem charge relays are used to divert charging current from the alternator on a towing vehicle and divert charge via the 12S socket to the leisure battery in a caravan or catering trailer. Do You need A TRM to charge a trailer? For trailer charging to operate, the TRM must detect a trailer is connected and a brake pedal input before charging will be present at the trailer connector. Adding the trailer battery charge relay and fuse into the battery junction box are NOT required...