Fitting new wiring loom to Austin Sevens

Coming to the end of a decades long restoration, or taking over an unfinished project, the question arises as to the route of the new wiring loom.

Definitive information issued by the Austin Motor Co. Ltd is unavailable.  Logically, if the battery is housed under the driver’s seat, or has been re-positioned under the passenger seat, then the loom has to run inside the passenger compartment to make the essential connection with the battery.  If the battery is housed in the engine compartment then the loom is routed outside of the passenger compartment.

Wiring looms
Custom-made wiring looms are only available for Austin Sevens from 1934.  Sevens built pre-mid 1934, did not have a wiring loom, the original wiring was simply laid from point A to point B and then, where convenient, loops of tape placed at intervals to keep them together.

Fitting the loom
a) battery is under the driver’s seat. 

RP Wiring 1.1

The wiring loom enters from the engine bay below the knuckle in the bulkhead between the two clips.  It then routed past the vent (photo) and along the floor through the battery box. 

Box 1.1



It is tucked tight into the inner side of the sill and the floor covering provides the protection.   The wiring is then taken around and up the front of the rear wheel arch, into the space under the rear seat and out through the floor pan to the rear lights.  The feed to the petrol gauge splits off after the floor pan grommet.  








b) battery is in the engine compartment.

Ruby diag 1.1

Routing the loom inside the car is not possible in the Ruby and Big Seven because the body sill goes below the floor level not above it.  Any wiring inside the car would be on the floor, visible and vulnerable to damage.

The logical route, front to back, is, therefore, down the bulkhead and then underneath the car on the offside (rhd) using chassis clips to attach it to the lower ledge of the body sill and entering the bodywork at the rear through the pre-drilled holes to connect to the rear lighting cluster. 

Where the rear light is mounted centrally below the rear window on the Ruby and some early Big Sevens the cable is routed in behind the backseat. 

Where the Big Sevens had the rear light cluster and number plate hinged to the boot lid the wire for the light enters the spare wheel boot and then into the bottom edge of the boot lid.






c) Specials
The key factor is the position of the battery and the routing of the loom follows from that and the above notes may help.


1. Wherever cables pass through a bodywork panel the correct size grommet should be used.

2. Fit a battery isolator switch to the front of the battery box for the internal wiring or across the battery terminal on a Ruby or Big Seven.

3. If you are making your own loom for an early model Seven, or Special, or modifying an existing one, then do produce a wiring diagram for future use by yourself or other owners.   When using black coated wiring throughout to save the  expense on small lengths of coloured wires then consider identifying wires with short lengths of coloured insulating tape eg. red, white. blue, red/white, red/blue, blue/white.


Flashing indicators
If you wish to fit flashing indicators whilst re-wiring then these are optional and their fitting must comply with the current (in UK) legislation.  Essentially the use of the front (white) and rear sidelights (red) is not legal and never was when this format was first introduced in the 1950s. 

Flashing indicator lights should be orange, at both front and rear, and conform with the legal requirements relating to obligatory direction indicators and to optional direction indicators which is covered by The Road Vehicles Lighting Regulations1989, Statutory Instrument 1989 No.1796.  Schedule 7 Part I: Requirements relating to obligatory direction indicators and to optional direction indicators to the extent specified in part ii. 

It can be viewed in full at  


Looms are available for most historic cars from: Auto Sparks, 80-88 Derby Road, Sandiacre, Nottinghamshire NG10 5HU.  Tel: 0115 949 7211.  Website:  e-mail:

See also:
Wiring Diagrams for the following models are available on this website:  The AC Tourer RP Saloon;  ARQ & ARR Ruby & Variants; CRV & CRW Big Seven

Wiring diagrams specific to a model of Austin Seven may be found in the Austin Motor Co. handbook and can be downloaded from

Fitting Flashers but keeping the semaphore signals.

Optional Flashing Indicators - Legal Requirements (UK only) (Flashing indicators; Rear retro-reflectors and Rear fog lamp)

This article, edited by Doug Castle, is based upon information provided by our members Chris Gill (RP), Andrew Jarmin (Ruby) and Doug Castle (Big Seven), October 2020.