Started to think about wiring things up. A few electrical questions; the photo below shows the back of the ignition warning light and the Dash lamp. I think both lamps have a connection missing. Should the ignition bulb holder have a 'loose' wire through the centre hole, with a soldered washer on the end (also spring loaded? coil spring?) The soldered washer provides the contact onto the centre of the bulb?
Does the Dash Lamp need the same arrangement? - if the centre wire is spring loaded, how does the switch mechanism, that draws the bulb forward away from the contact?
ignition light.jpg (101.69 KiB) Viewed 4634 times
where are the contact terminals on the wiper motor? looks like there is an earth on the side but where is the live contact?
I think this is the sort of arrangement on the dashlamp.
The chrome cover has a keyway which engages with the outer ring of the switch/bulb holder.(the outer ring should be turned so the keyway is at the top)
The centre contact for the bulb has a pair of protruding lugs which engage with an angled slot.
When the outer ring turns the spring loaded contact moves up and down the slot, thus making contact with the bulb when ON or creating a gap when OFF...
The bulb is fixed in its own keyway and doesn't move.
The outer ring is earthed through the dash panel.
On mine the bulb is a bit loose when the contact is withdrawn and the light is off, but it all works with a satisfying click!
Thanks Peter, you have saved the day once more! - I think that I can sort out the Dash light from your superb photos. Am still stuck with the ignition light. I gather from another thread that it should have a 2.5 Volt - 0.5 Watt Bulb giving a total resistance (when the bulb is warmed up of, {I will need to read again, but something like 20 - 40 Ohms} -- I think that it must have the same arrangement as the Dash Light - a spring loaded contact?
I have just attempted to wire up (I know that it is not right for year but I is all that I have to hand), the stalk mounted horn/dip switch assembly. I can only find three contacts. They make sense as the switch over contacts for the dip switch, but I cannot see anyway that wires can be got to the horn switch. I assume that it will just 'earth' but it will need at least one wire? I cannot see how it can share the lighting contacts, unless you can only sound the horn when the lights are on?
now while I am picking everyone's electrical brains, the wiring diagram shows a dotted line linking the F1 and F2 terminals on the PLC. I assume that means there is an internal connection. If so why is there an F2 terminal? should something be connected to it?
1933 Minor Wiring Diagram.jpg (100.08 KiB) Viewed 4601 times
Re. The horn circuit.
The neg wire from the horn is the contact to earth through the horn push.
Re. Ignition warning light.
On my version of the ignition warning light the centre contact is fixed and is more of a pin than a flat ‘blob’.
The reason for this is that the bulb doesn’t screw in to the holder. It’s just pushed in and held by pressure from the spring against the screw-on lens ring/cover.
The spring is between the base and the bulb, not under the base as in the dashlamp.
You’re right in assuming the centre wire is missing.
On the original warning light there’s a resistance wire, of a nominal 30 ohms, wound round the body of the unit to limit the current flow.
The bulb is a 2.5 volt, 0.5W, 0.2A, MES
If the resistance wire is missing or damaged there are a couple of fixes:
1. Use the original 2.5V bulb and fit a modern resistor to the unit (I think available from Ian Harris).
(If fitting a resistor bear in mind that the unit has to pass through the small hole in the dash, also the retaining ring and spring has to fit over the body.
2. By-pass the resistance and fit a 6V 0.2A bulb.
This is commonly done. The bulb may be a bit hotter and apparently there’s a slight chance that because the resistance is not as per the original the light may glow even when the ammeter is showing a charge, (annoying, but doesn’t affect the charging operation).
This doesn’t happen on my car and the light works fine with the 6 volt bulb.
Re. F1 to F2.
My car has a CFR cut-out, yours may be a CF3, so I can’t be sure the same connections apply.
According to my limited knowledge F1 and F2 aren’t linked internally in the PLC switch. The link is a short external connection.
It’s all to do with the variable charge rates (Winter / Summer or High / Low)
Let me know if you want elaboration !
Again, Thank you Peter - off to Middlesbrough now, will be able to use your photo + info to make the contact for the Ignition Warning light this afternoon and have another go at F1 + F2.
It is the Horn Push switch and Dip Switch that I am still unsure about. There are only three terminals that I can see (look to be for the Dip 'switch-over' {one common that 'flips' between two posts} ) - the contacts for the horn are simply bridged by the horn button contact dome; but, it looks like one of the horn contacts is connected to the Dip Switch common terminal + am not sure where the other side of the Horn contact goes to.
I think I must have got a bit confused with this switch, it can only be the Dip Switch. The button on the end that I thought was the horn msut be a temporary Dip? Will need to try to find the horn switch that I have somewhere that fits to the steering column bracket.
That is definitely a horn/dip switch arm. From the wiring diagram you can see the 6V line that is switched to the main and dip beams, and the single wire from the horn which sounds when the switch grounds to the body of the switch - hence no earth wire (although you might want to fit one).
So the hard-wired side of the headlamps go to ground, while the hard wired side of the horn goes to 6V coming from the + terminal on the cutout. Does that make sense?
Hi Ian - amazed that such a simple switch is presenting me with so many problems; must be old age! - the wiring diagram makes sense as does your explaination. But when I test for continuity between the '12 O'clock' contact (wiring diagram) {Black wire = dipped fillament} and the '2 O'clock' {Horn earth}, they are connected.
Similarly when test for continuity between the '6 O'clock' and '4 O'clock' contact, they are connected. Also there is no obvious way of connecting a wire to the Horn positive contact {horn '4 O'clock}
dip switch wiring.jpg (26.88 KiB) Viewed 4520 times
I sympathise with your puzzlement having been there myself !
I don’t know if your switch is the same but here’s how mine works in principle.
Firstly the 3 terminals in the base are for the lights and have nothing to do with the horn.
1 is the supply for the headlights from ‘H’ on the PLC switch.
1 goes to the main beam headlights (via a junction box)
1 goes to the dip beam (also via the junction box)
The horn works by making an earth connection inside the switch.
The body of the switch unit must be earthed, either through the steering column or a separate wire to one of the fixing screws.
The single wire from the horn passes through a hole in the base and is fixed to the internal centre contact with a grub screw (or soldered on directly as mine). This contact is insulated from the body of the switch by a fibre disc. The (bakelite) horn button is also insulated and has a metal disc (‘A’) attached to it by a screw. A spring holds the button in the raised / off position.
When the button is pressed the spring compresses and the attached disc (‘A’) moves into contact with the plate (‘B’), which is earthed through the fixing screws and body of the switch, completing the circuit and sounding the horn.
Peter, the quality of your photos must have John Haynes a bit worried! Your switch makes sense; mine must be off a supa-dupa, go-faster vehicle or missing a lot of bits! Have just checked again, there is electrical continuity between the three Brass Posts/contacts in the 'Dip' section and the three screws/contacts in the 'Horn' section of the switch.There is no hole in the bakelite for a wire to pass through into the 'horn' section to enable an additional base plate to be fitted to the assembly so that I end up with the same arrangement as yours. The two brass contact/fingers that are attached to two of the screws that pass through into the 'horn' section, look to be there for a reason?
Hi John,Sorry if I oversimplified the problem.
The 1935 Morris 8 has the dip switch and horn on a stalk.
Again I don't know if yours is similar but here's a wiring diagram which may be useful.
Electrickery makes ones brain hurt! - gave up and fitted the bonnet and rear wings. Having a blitz this week to see if I can get it to the drive-it stage!
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rear wings fitted.jpg (77.51 KiB) Viewed 4429 times
Now back to the Questions: which of the two 'eyes' on the brake pedal should the linkage to the brake cross shaft be fitted? top or bottom? If I fit a brake light switch, where should I connect it/ mount it?