Wiring Harness Adapter For ARB Compressor. Adapter Harness for ARB compressor to utilize sPOD switches and Source to control compressor, front and rear lockers. Note: This adapter harness is Not required for the twin ARB compressor if you are not using the compressor for lockers! All that is required is to attach the 1 purple wire from the ARB harness to any of the positive outputs on the sPOD's Source.