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LUCAS light switch differences



Many of us with either iron bullets or Redditch bikes will be familiar with the Lucas U39 headlamp switches, but let's take a look at some other variants, some of which were no strangers to RE's



Firstly, We need a key to decode the letters on the switches



OFF - All lights off
C - Half Charge
H- High Beam or Headlamp
L - Low Beam
P - Parking lights
T - Tail light
TEST - Not quite sure, sorry




This is the Indian switch that is fitted to the iron barrelled bullets. Clockwise we have Parking (tail and pilot lamps), OFF, Headlamp. The high and low beam is on a separate switch.








This U39 would have been fitted to older RE's. It is a three position as above but the positions are changed, clockwise being OFF, Low beam, High beam.





Although there were production and detail changes, this shows the rear of a typical Lucas switch, although the grub screws are missing from this one.







This earlier Lucas switch was made around 1936. The C position cut down the charging rate when the lights are off, to avoid the possibility of overcharging the battery. The positions are OFF, half Charge, High beam, Low beam





This is an RS 39, which was fitted to overseas military RE's during the Second World War. The T position lit the tail lamp only. This fitted in with other army vehicles that had convoy lighting, and could also be used for sending a signal from an advanced position. It has OFF, Tail light, Low beam, High beam.





The motorcycles that resided in Britain were fitted with blackout masks on the headlamps, which basically ended the need for a Low beam. This switch; the U39-L15, was more suited than the RS 39 above. Unfortunately, I have no idea what the TEST position was used for, but the others are OFF, Tail light, Headlamp.







Here for reference, is a British Army Land Rover Lucas switch. CONV. is a small focused lamp with a tight beam that points forwards from under the front of the vehicle. In a convoy, the vehicle in front of you has a small white disc painted low down on the back, and you drove very close to it, keeping your light on the white disc ahead, and sometimes that was all the light you had at night! You hoped to hell that the lead vehicle could see where he was leading you all! The many switch positions, allowed for just about any needed combination of lighting. Clockwise, these are, Headlamp + Side lights + Tail light, Side lights + Tail lamp, Tail only, OFF, Convoy lamp, Convoy lamp + Side lights.





Hope this little rambling has been interesting to you.

P.S. Does anybody have an old 4 position RS 39 available (OFF, T, L, H), as Tornado wants one for Christmas!



That bullet wants for nothing!

Interesting info, thanks for posting

Lucas type U39 on 'That site' with only 2 days to go Scaly.

Thanks for thinking of me, but I really need the 4 position RS39.




Only way so far that I have worked out how to have the tail and pilot lamps on with the headlamp off!



There again, if somebody knows a way that will allow the pilot and tail to still work with the ignition in P as well as being selectable with the ignition in ON, without powering the lights when the ignition is supposed to be OFF!

Sorry for getting your hopes up matey, I only spotted the '39'.

That's ok, they are very hard to get hold of !

I have found RS39 switches for sale, for $125 each, I assume that would be a no.

Ouch!



Thanks for looking, but even my quest for perfection falls short of that amount of money! Crikey!

That must explain why army vehicles used to have the diff on the rear axle painted white for night time convoy use