tripack apu fault

I've got a 2014 tripack and getting a fault that is getting an heater contactor input fault. I've heard that usually means the inline fuse has blown but as of yet I've to find the connector or an inline fuse anywhere near the control board the relay pannel or in the engine compartment. Does anyone know where this connector is located? Apparently this fault is keeping me from doing a dpf regen which has caused my apu to stop running due to too much time since regen.