Notes on Front Wing and Cowl Wiring
ALWAYS disconnect the battery when dealing with the lamps or horn and remember that these items are live when the ignition is switched off. After passing through the engine compartment the wiring loom is divided in two. One branch passes through the right inner wheel arch whilst the other passes through the left side. From here on the wiring is quite simple, although it is subject to quite severe conditions as water and grit are thrown up from the tyres. Beneath the front wheel arches the original loom lacked the protection from an outer sheath. In the diagram above I indicate braided sleeving in grey. It is quite cheap and is available on Ebay or companies like "AES (Auto Electric Supplies)". If you rewire your Morgan, I strongly recommend it. If you only want to tidy up your wiring, split braided sheath is available. It is springy and fits around bunches of wire without disturbing them. Do not worry about it retaining water. The braided nature of the loom ensures good drainage. Always make sure you use rubber grommets where wires pass through the bodywork. Any coloured wire (+) that wears through can short out on the body (-) and blow a fuse.
The above diagram shows the wiring of the right hand wing. The wire colours to the left hand wing are different. The right headlamp has the same colour wires as the left headlamp, but a green wire with a white tracer is connected to the right flasher and a green wire with the red tracer is connected to the left flasher. A black earth wire and a red wire with black tracer are connected to the right sidelight whilst a black earth wire and red wire are connected to the left sidelight.
Front LampsFigure 2
The following wiring under the front wing and cowl box must be disconnected before the main loom is removed.
The horn is mounted on the rear of the cowl box and and has two 6.4mm male Lucar terminals. The horn only requires one connection and if your car has the standard loom a purple wire with a black trace is connected via a female Lucar connector. The body of the horn acts as the earth connection. If you have renovated the paintwork on the cowl box make sure the horn and its fixing bolts make good contact with bare metal.
The headlamps originally fitted to Morgans in the nineteen seventies were 7" sealed beam units with 60 W main beam and 45 W dip beam filaments. No side light bulbs were included in the unit. The problem with them was that the slightest damage to the lens could lead to complete failure of both filaments. Sealed beam lamps were not too expensive and were easy to replace. I have kept a few from the old days, but many people have changed over to H4 units utilising halogen bulbs which for the same wattage and are much brighter. Holden Vintage & Classic supply a good range. Xenon lamps are even better, but always be careful to try and keep within the limits of the original wattage, otherwise you will have to consider upgrading your wiring. Underneath the car three wires can be seen passing through the wheel arch beneath each headlamp. There will be a blue wire with white tracer, a blue wire with red tracer and a black wire going to each headlamp. Trace these wires back and remove them from their female bullet snap connectors. To remove the headlamp remove the small screw at the bottom of the chrome rim. Lift the rim upwards whilst carefully pulling the base towards you. Two lugs at the top of the backshell housing retain it. It may require a bit of a wiggle to free it, but it should come off easily. Having removed the rim you will see a chrome retaining ring surrounding the glass lamp unit. If you want to remove the complete unit do not undo any of the screws around the retaining rim. There are four screws that secure the black backshell to the headlamp nascelle and they do not go through the chrome retaining rings. When these four screws are removed, the headlamp assembly complete with backshell and gasket will be released. If the sealed beam unit alone requires replacement then you only need undo the four retaining rim screws. Do not to loosen the alignment screws at this stage.You may find an "H4 Pigtail" (see Figure 3 below) fitting connected to the three male Lucar blades on the back of the sealed beam unit. In this case replacement simply involves unplugging the old sealed beam unit and plugging in the new one. When replacing a sealed beam unit which has been installed with female Lucar connectors, hold the lamp with the rear facing towards you and the horizontal Lucar blade on top. The black wire is connected to the left hand vertical earth terminal, the blue wire with red tracer (dip beam) is connected to the top horizontal blade and the blue wire with white tracer (main beam) is connected to the right terminal. The black earth wire is essential because the glass construction of the lamp insulates the filaments from the body of the car. During a rebuild it is wise to box and label each lamp assembly, carefully noting the side to which they belong. This helps minimise the effort when realigning them. When rewiring the car be sure you have fitted a rubber grommet to the wing inside the lamp nacelle.
Since the beginning of the millenium the law has forced Morgan to fit integral side lights in the main beam unit. I believe Morgan fitted wing mounted side lights on cars until around 2010, but since fitting the side light in the main lamp unit they did not wire the wing lamps up. Ironically the owners could and usually did. If you own a post 2010 Morgan I believe you can still fit them yourself (if you want to risk drilling a big hole in the front wing of your shiny new car). Wing mounted side lights changed in design over the years. The lights on my 1972 car are the type I describe here. They are the Lucas L516 units with BA9s 4W bulbs. To change a bulb is straightforward. By undoing the screw at the rear, the inner lamp holder can be withdrawn complete with its chrome bezel. Care is needed not to over stretch the wires. Gentle pressure on the sides of the bulb holder allows the bezel and lens to be removed. The bulb can then be accessed and changed. The base of a Lucas L516 unit incorporates a hollow fixing bolt which passes through a rubber plinth, the upper wing and the main front wing support bracket below. This bracket has often been written about over the years, because if it does not fit the wing properly and is not bolted up tightly, the front wings can crack. Unfortunately the main fixing for the wing bracket is the hollow bolt on the base of the sidelight fitting. If the nut is done up too tight it can damage the inside of the sidelight. The situation is just as bad when removing the sidelight from the car. If the nut is corroded, undoing it can make the bolt turn and ruin the inside of the lamp casing. If you are unlucky and damage it, AES or Holden will supply a Lucas L516 for around £30 The right hand sidelight has a black earth wire and a red wire with black tracer connected to it. On the left hand side a red wire along with a black earth wire is attached to the light unit. Morgan stopped fitting L516 sidelights in 1976 and changed over to Lucas 1130 units which are also available from AES & Holdens.
The flasher lamps on traditional Morgans have changed little since 1970. They are Lucas L794 units and are commonly available from Holdens and AES (click links above). Lenses and retaining screws are available at relatively low cost. The amber lenses can also be replaced with clear ones which are used with amber bulbs. When changing bulbs make sure they are 21 W with a single contact. Removing the unit from the front wing is straight forward. Unscrew and remove the indicator lens then remove the two bulb holder bolts and withdraw the complete unit along with the rubber plinth and wire. Morgan wings are undersealed at the factory, but on older cars this has often weathered and failed, which leads to difficulty when undoing the retaining bolts. When refitting the indicator bulb holders, I used stainless button head bolts which are tightened with allen keys. They are not cheap, but they make life so much easier when removing them. If you study the circuit diagram in the 'Morgan Owners Handbook' it shows the earth connection to the front indicators with a letter B alongside. This suggests (according to the circuit diagram key) connecting a black wire to earth. Morgan however used only a single live wire, because the bulb holder is earthed via the retaing bolts to the front wing. When rewiring the front indicators, it is important to ensure that the green wire with a white tracer is connected to the right flasher and the green wire with the red tracer is connected to the left flasher.