18-03-2018, 12:41 PM
(This post was last modified: 19-03-2018, 05:33 AM by Tony Press.)
(18-03-2018, 08:35 AM)JonE Wrote: thanks Tony - very comprehensive. Do you see Stuart's comment about the series/parallel applying to earlier cars still then? It was the '25 wiring diagram that was confusing showing just one wire! I can see how a two wire system, if it were an earth return, can be changed at the switch from series to parallel through the lamps' dual filaments (always operating together, presumably) in an old fashioned bulb... but we change the method of functioning by wanting to select each side of the 21/6W?
The early CAV etcetera headlamps didn't have a high and low beam - only full on or dim (later full on or sidelight).
The earlier wiring diagrams showing the CAV switch panel are deceptive - the circuit from the dynamo only shows a single line but there are in fact two end wires shown, as with the headlamp circuit, so I believe there are in fact two wires to each headlamp.
The CAV switch panel has a headlamp switch and a dim switch but never having studied one don't know how this operates.
The Lucas SM3 switch panel simply switches feed between the main and secondary filament in the bulb.
Cheers, Tony.