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I started by refurbishing the door cards 6 weeks ago and somehow the job list grew.
I have previously enquired in this Parish about the sunroof... After hours of fiddling and experimenting with different seal profiles for the metal lid I think I am almost there. I shall post pictures another time in case it is of help to anyone. And I am going to enlist the help of Headliner World for the headliner... Whether that is just materials or full fitting. It is a custom job as the standard GRP liner won't fit because of the cassette.
Anyway this question is about the central locking. I have what is presumably the original, old-style actuator on the passenger side - what I think is a solenoid, as it clunks in and out when operated by the ski slope switch. But there is no link rod to the door lock (so even I could work out why it is not working ). I fashioned a template rod with some coat-hanger wire... It's difficult to tell if a properly fabricated rod (I have ordered a 3mm mild steel rod to bend to shape, and some clips) would actually lock and unlock properly because my instinct is that the back-and-forth travel on the actuator isn't enough. No more than a centimetre I would guess and that is being generous.
I guess they wear over time...? And maybe problems with the throw are the reason the rod was missing when I went to investigate?
Anyway, I looked in the driver's door and there is no actuator in there at all. Like the passenger side though, there are two wires that have reverse polarity and are operated by the locking switch on the ski slope (i.e. toggling the switch one way makes one wire positive and one ground, and vice versa).
On neither side are there any more wires… But I had understood that the master motor on a central locking system has 5 wires; 2 being switched polarity wires to operate the motor, but 3 extra to do the witchcraft and – having sensed the position of the lock – to tell the slave motor what to do…? I am at the limit of my understanding here – presumably it involves relays somewhere?
My initial plan was to swap these into both doors –
As they have almost an inch of throw which I think – when properly fitted – should give a much more positive lock/unlock action.
My question is – if I did that, presumably both locks would operate inside from the switch on the ski slope? That would still be handy, mainly to be able to let a passenger in without having to lean over. But would there be any external central locking i.e. if I were to lock the driver’s door with the key, would a 2-wire set-up also lock the passenger door? I am guessing not? But if I fit a 5-wire master motor to the driver’s door -
...so it can speak to the passenger door motor, where would I run the extra 3 wires to? Perhaps the ski-slope switch?
Thanks for any help – I have looked through the threads for answers so sorry if I am duplicating a well-worn topic. Most of the threads seem to be about installing keyless entry which I am not really fussed about (I am trying to keep the car original where possible) – but maybe keyless would be an easier option if in effect that would operate 2 slave motors using the ski-slope relay… Which would save routing 3 new wires into the driver’s door, which would be a pain in the ****.
I do not see any reason why those would not work. But I believe they would only work off the ski slope switch. My 78 US model did not have any lock activation off the outside door key.
Thanks Doug. It got very complicated very quickly. I have unlock and lock relays at the base of the A pillars but working out where to send the 2 wires from the master actuator (one grounded when the driver's door is locked, and one when it is unlocked) made my head hurt. I have ordered a controller unit because that way there is somewhere simple to plug the white and brown wires of the master actuator into... And I think it also has white and brown wires that I can take to the rocker switch on the ski slope. Currently it is a +12v switch to the relays, but if I make it a ground switch that should tell the controller what to do in the same way as the master actuator wires do. And the relays will just be redundant.
That is the plan anyway! So hopefully the doors will lock/unlock from the switch, but also by putting a key in the driver's door. Also from the remotes of course but I doubt I'll use them as it seems a bit vulgar to get into a '78 car without a key ... And certainly no flashing indicators
My left hand door would not lock when I brought mine. Not exactly sure what caused the failure - whether is was the previous owner modifying a right hand actuator for the left hand side - or it just wore out.
After finding out the price for a replacement, just went down to Supercheap and put a $20 actuator in (very similar to your link). Might not look the best - but has worked well for a few years now
I did not need any controller or anything else, simple plug and play, so not sure what the difference between a 78 and 80 is.
I do remember I had to put sewing machine oil on the key to get the locking mechanism to work smoothly as well
Thanks Steve. I have no idea what I/the PO have done. When I plugged in one actuator on the LHS it worked, when I put a second on the RHS it didn’t. Not sure if I reversed wires and fried something or if there is a relay issue and the PO had had a play and given up (hence missing components). Either way I felt remote locking would help, not because I want the remote function, but because a 2021 controller module(even a cheapie) should outperform Lucas. The switch is currently fed by a 12v... that is partly what confuses me because the output from the 5 wire drivers door actuator is a ground. I might understand it if I studied relays in a bit more detail, but my Neanderthal approach is just to swap the 12v to the rocker with a ground wire, and use the switched ground wires to operate the controller in the same way the actuator wires do.
But if anyone is handy with electrics and sees a flaw in this cunning plan, and can tell me before the weekend, that would be great,
I fitted the remote controlled unit yesterday (Right Click) and it was simple even for me. Now both doors lock from operation of the driver’s door paddle, or key barrel (and remote of course). Plus by changing the ski slope switch from a switched live to a switched earth, and connecting to the relevant control unit wires, the ski slope switch also allows locking from inside.
I may use the wire that disables the starter (or fuel pump) as that way there is a discrete immobiliser.
Really recommend a kit like this if you have central locking trouble and don’t have an electronics degree or a sadomasochistic fetish for Lucas.
Central locking - '78 coupe
). I fashioned a template rod with some coat-hanger wire... It's difficult to tell if a properly fabricated rod (I have ordered a 3mm mild steel rod to bend to shape, and some clips) would actually lock and unlock properly because my instinct is that the back-and-forth travel on the actuator isn't enough. No more than a centimetre I would guess and that is being generous.
... And certainly no flashing indicators 
