Joined: Aug 2017 Posts: 110 Threads: 24
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About to embark on a rewire from scratch. Can anybody point me in the direction of what colour wire should be used for each function, eg headlights in blue, dynamo in yellow, or whatever? I tried a search on the old forum without success.
Thanks, Bob.
Joined: Aug 2017 Posts: 1,017 Threads: 53
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Location: The delightful town of Knaresborough, North Yorkshire
This might be useful, but what year is your car?
This car is wired NEGATIVE earth.
It always has been negative earth,
positive earth was not introduced until 1936.
item Colour of wire Position of wires
Negative battery lead to the starter motor casing, and to the body, bolted to the battery box.
Black
The positive battery lead is connected to the starter motor terminal. Black
Everything else is earthed to a nearby body earth point. Black
Everything is powered by a thick wire from the starter motor which goes
to
the isolator switch behind the dashboard
Yellow/black
This thick wire continues from the isolator switch. to the ammeter Yellow/black
From the second terminal of the ammeter to electronic voltage regulator Brown
From the second terminal of the ammeter to Ignition switch , A. White/purple
From ignition switch , A. to Non-ignition fuse White/purple
Linked from non-ignition fuse to Lighting fuse White/purple
from Lighting fuse to Light switch White/purple
From Light switch to Dipswitch via fuse Blue
From dipswitch to Main beam headlight via junction box in car Blue/white
From dipswitch to Dipped headlight via junction box in car Blue/red
From light switch to Fuse, then Sidelights via junction box in car Red
All sidelight wiring from junction box to Front sidelights Red
All sidelight wiring from junction box Through o/s roof and across in boot Red
NOTE…
SIDELIGHTS AND
offside INDICATORS
ARE BOTH RED
RED
From ignition switch, IG to Ignition fuse White
From ignition switch, IG to coil White
coil to distributor White/black
Ignition fuse to Brake-light switch Green/
purple
Brake-light switch to Brake-lights Green/
purple
Junction
Front indicator offside Underbonnet
junction box Os wing red Os wing
Rear indicator offside Underbonnet
junction box Os rear red Os roof
Front indicator
nearside Underbonnet
junction box ns n/plate red Os wing
Rear indicator nearside Underbonnet
junction box ns rear red nearside roof
j/box f/box j/box red b/head
Brake lights brakelight switch Nearsides st lt Green/
purple Nearside roof
Offside Brake lights to nearside Brake lights Os st lt Gr/purp boot
Centre st lt ns st lt cent st lt Gr/purp boot
Centre tail Ns tail cent st lt red boot
h/light h/l sw f/box blue dash
h/light f/box Dip sw blue In car
h/light main Dip sw j/box Blu/wh In car
h/light dip Dip sw j/box Blu/red In car
h/light main j/box Os h/lt Blu/wh Os wing
h/light main j/box Ns h/lt Blu/wh Ns wing
h/light dip j/box Os h/lt Blu/red Os wing
h/light dip j/box Ns h/lt Blu/red Ns wing
coil Ign sw coil wh Os wing
coil coil dist Wh blk Os wing
Dynamo D dynamo f/box yellow Os wing
Dynamo D f/box reg yellow b/head
Dynamo F dynamo fuse green Os wing
Dynamo F fuse reg green In reg
Horn sw j/box horn yellow X BULK
Horn horn aux purple X BULK
wiper aux wiper/mtr purple os/roof
j/box aus Ign fuse j/box pink b/head
various
item earth black various
Below is a basic A7 diagram from about 1932, but with 1950s headlight wiring colours.
This comprehensive diagram is more accurate, but gets a bit complicated!
This lets you look up a colour of cable, and see what it connects to.
Black Many things earthed a nearby body earth point.
Yellow/black Power from starter motor to masterswitch
Yellow/black From masterswitch to ammeter
Brown From the ammeter, via a fuse to electronic voltage regulator
White/purple From the ammeter to Ignition switch , A.
White/purple From ignition switch , A. to
Non-ignition ‘aux’ fuse
White/purple From non-ign fuse link to Lights fuse
White/purple from Lights fuse Light switch
White From ignition switch, IG Ignition fuse
White From ignition switch, IG Coil (not fused)
White/black coil distributor
Red From switch on steering wheel to junction box under bonnet and
to
Offside indicators
Red From light switch, via fuse to junction box in car and to all Sidelights
Blue Light switch, via fuse to Dipswitch
Blue/white From dipswitch Main beam headlight via junction box in car
Blue/red From dipswitch Dipped headlight via junction box in car
Ignition fuse Brake-light switch Green/purple
Brake-light switch Brake-lights Green/purple
Re ind os j/box Os rear red Os roof
Fr ind ns j/box ns n/plate red Os wing
Re ind ns j/box ns rear red ns roof
j/box f/box j/box red b/head
Stop lts St/lt sw Ns st lt Gr/purp Ns roof
Os st lt Ns st lt Os st lt Gr/purp boot
Centre st lt ns st lt cent st lt Gr/purp boot
Centre tail Ns tail cent st lt red boot
h/light h/l sw f/box blue dash
h/light f/box Dip sw blue In car
h/light main Dip sw j/box Blu/wh In car
h/light dip Dip sw j/box Blu/red In car
h/light main j/box Os h/lt Blu/wh Os wing
h/light main j/box Ns h/lt Blu/wh Ns wing
h/light dip j/box Os h/lt Blu/red Os wing
h/light dip j/box Ns h/lt Blu/red Ns wing
coil Ign sw coil wh Os wing
coil coil dist Wh blk Os wing
Dynamo D dynamo f/box yellow Os wing
Dynamo D f/box reg yellow b/head
Dynamo F dynamo fuse green Os wing
Dynamo F fuse reg green In reg
Horn sw j/box horn yellow X BULK
Horn horn aux purple X BULK
wiper aux w/mtr purple os/roof
j/box aus Ign fuse j/box pink b/head
various
item earth black various
Joined: Aug 2017 Posts: 110 Threads: 24
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Thanks very much indeed!
My car is a 1930 RK, but has modern extras like indicators and Tacho etc.
Joined: May 2018 Posts: 2,104 Threads: 110
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Location: Llandrindod Wells
Car type: 29 Special, 30 RK, 28 C Cab
Hi Bob
I rewired my 1930 RK a few years back. Originally most of the cables would have been armoured (ie wound with aluminium shielding). I replicated that and used the Seven Workshop as a supplier and the only colours available were black for the single core, red and black for the two core and red black and a mucky green colour for the three core.
I rewired the car as it would have been in 1930. I decided black as earth, red as live. There are precious few cables and no loom. Check out Woodrow for a wiring diagram and Rinsey Mills restoration book for cable routing. (Note the cables to the coil and horn are black fabric coated.)
Extras such as indicators, brakes etc I wired completely separately using a live taken direct from the battery to a modern fuse box under the passenger seat. My indicator switch is on the transmission tunnel and brake switch on the passenger side cable. This made things so much easier in routing cables along the chassis (and out of site).
Hope this helps
Howard
Joined: Sep 2019 Posts: 15 Threads: 0
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Location: Northern Ireland
Car type: PD 1931
Hi, when I bought my Austin seven PD 16 years ago the previous owner had rewired it using a cable of yellow for all the wiring
and I had to start from scratch, I found Autosparks limited of derby very helpful and an amazing
Selection of colours and sundries.
Stephen
Joined: Apr 2019 Posts: 244 Threads: 13
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Location: Toronto
Car type: 1930 Boat tail tourer
this is so very helpful! Funny I am sorting wires for my more modern classics and was wondering when the British car industry standardized wire colours.
Came online and here it is.
However, I don't see the diagrams - is that just me?
thanks all
Joined: Aug 2017 Posts: 1,976 Threads: 90
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Location: Ripon
Unless you are a slave to originality I'd recommend using BS wiring colours. This will mean that any competent auto-electrician will be able to deal with electrical problems in your car after you have either sold it or died!
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Location: Upton upon Seven
Car type: 1931 RN, 1933 RP
16-07-2021, 10:11 PM
(This post was last modified: 17-07-2021, 04:34 PM by Roland Alcock.)
For completeness, this is what Lucas finally settled on post war.
Brown means live all the time (=connected to the battery post)
White means brown that has come through the ignition switch and can therefore be switched off with a key (coil, fuel pump)
Green is white that has gone through a fuse in the fusebox and is therefore (like wipers) switchable and fusedBrown
Purple is brown that is fused and therefore permanently live (horn and interior lights plus radio)
Blue is lights. Power comes from the brown to the switch so that lights can be switched on whilst the ignition is off. [Note. sidelights (red) are fused but headlights are not.]
The supply from the headlamp switch is blue as far as the dip switch where it goes to blue/red for dipped and blue white for high-beam. From the switch it is red/green until it reaches the fusebox where it becomes red only. The panel lamps are red into the switch (comes on when the sidelights come on) and become red/white as they travel to the individual bulbs
white/black is from coil to dizzy plus to RVC type distributor.
Black is earth.
green/red is right indicator
blue/white is left indicator
green/black is fuel tank sender
green/purple is brake lights (therefore fused and comes on after the ignition is live)
1931 RN, 1933 APD
Joined: Aug 2017 Posts: 607 Threads: 19
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Location: Hampshire UK
Hi Roland
Shouldn't that first line read "Brown means live all the time" ?
Joined: Aug 2017 Posts: 176 Threads: 11
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Location: Upton upon Seven
Car type: 1931 RN, 1933 RP
Hi John
Yes of course it should. No idea how that happened!
I’ll see if I can edit it.
Roly
1931 RN, 1933 APD