The black device is just a few resistors molded into epoxy. The
different tank probes connect to different points in the resistor
network and the led panel sees the total resistance and lights up
accordingly. You have an early Westy so it is possible that your led
panel has the transistor to shut off the pump power when the tank is
sensed very low. If you remove the led panel screws and look at the
circuit board it is easy to see if you have the large round metal
transistor can. This should jumpered around as it is a problem under the
best of circumstances and was deleted after the first few years.

Mark

Neil2 wrote:
> Hey volks,
>
> On my 81.5 Westy there are about four water level probes with leads
> connected to them.  I believe they are (from top to bottom) Green, Yellow,
> White, Black.  Three of mine connect to some sort of potted device mounted
> on the aft wall of the compartment fwd of the water tank.  Inside, it looks
> like black potted material.  It'd be nice to know what the function of this
> component is but I'm more interested in knowing why my black lead exiting
> this component is hanging in the wind and not connected to the corresponding
> probe.  I can't see any indication it was ever connected to anything.  It's
> long enough to have reached the black probe so I wonder.  BTW, My sink pump
> whirred away when I connected it's leads directly to the battery but that's
> the only action I've ever had out of it.  No water ever flowed when
> attempting to use the faucett.
>
> Anyone know the story?
>
> Also, there are two leads (black & yellow) from the water pump (below the
> sink) heading aft.  Anyone know if these simply go to the power source or
> whether they are affected (connected) to the circuit where the mystery
> component is located?
>
> Also, does anyone know much priming is required to get the OEM pump to work?
>
> --
> Neil
> '82 Diesel Westy
> Me other car is Swedish
>