The following information can assist in understanding how to add electric brake control capability to 2.5 and 5 ton trucks in the M35, M54, M809, and M939 series.
Military trucks use a 24 volt electrical system but commercially available electric brake controllers operate on 12 volts. An interface between the 24 volt system and standard 12 volt civilian components must be used. It is recommended to use the ST 340 DC-DC converter for powering the electric brake system. This converter takes the trucks 24 volts and drops the output down to a regulated 12 volts at up to 20 amps continuous load. The 24 volt input should be fused (for safety) and switched so the converter can be shut down when not needed.
An interface on the brake light circuit is also required. The brake controller must know when to apply the brakes and this is usually done by sensing the brake light circuit. Our 4M-6003 is designed specifically for this. It adapts between the 24 volt truck system and the 12 volt electric brake controller.
The brake controllers output wire should be run to the vehicles trailer receptacle socket position K. Position K will pass directly through the trailer cable (such as 7728811) and through the UTC2412RVEB converter, terminating as the blue wire on the UTC2412RVEB output connector.
UTC2412RVEB will convert the trucks 24 volt light circuits to 12 volts for regular civilian trailer use. It does not control the electric brakes; the electric brake circuit simply passes through the converter.
Please see individual product pages for additional information.