Wiring for front roof

My front roof circuit has a high resistance connection before the fan, which is the first unit shown on the wiring diagram. There must be a connection point prior to the fan as it is a "spur", and not in series with the lighting. The power to the LP detector does not falter, so the fuse and wire to that point is ok, since they are on the same circuit at the panel fuse.
Does anyone know where there are or is a connector after the spur for the LP detector and the fan????

The factory diagram is too rudimentary to show it.

Thanks,

Rusty