Door lock on an early car, how do they work!!!

[Martec]

At the S type seminar at Castle Bromwich recently I spoke to Bob Bates about the internal wiring of the drivers rear door lock. The Jaguar wiring diagrams just show a space with 3 wires going to it and motor shape.

A friend allowed me to have the lock we removed a month ago and a length of wire and the terminal plug to test my lock in situ. I have now opened up the lock and it is pretty basic, metal mechanical links with a very small motor operating the remote lock/double lock and unlock.

The motor winds one way to lock and the other to unlock.

There are 5 wires to the lock assembly, 2 are for the micro switch that operates as the door is opened or closed, the other 3 operate the motor along with 2 micro switches. One of these switches is duff so fortunately it stopped in the unlock position, one 2 pence micro switch means no more electrical locking on that door and I can't see much point in replacing the door lock for now.

My symptoms were none operation and no continuity across the 3 terminals at the lock. I have sent information and a wiring diagram of this lock to Bob Bates as he may find it useful.

I hope no one else is trouble by this lock as its a s>d to get out and back in.

Brian

[oldtimer]

Hi Martec,
Have just read through the above 2-3 times

Does the motor have a small spur gear on the spindle driving a rack?
Did you discover how the motor engages the first and second lock?

You say, the motor winds one way to lock and the other to unlock - with that in mind, is the second lock a part of that process or a remote function?

You say there are 5 wires to the lock assembly, 2 are for the micro switch that operate as the door opens and closes. I can't think where that switch is. Is it in the door jam ? If so where?
Do the internal lights come into this?

Now we come to the other three wires, I guess two wires are colour coded for motor clockwise and anti clockwise rotation. The third black being earth. Are the 2 micro switches, motor, end of travel, off switches

Is the defective micro switch that you refer to removable? If so would it have been possible to replace it with one from the spare lock assembly that you have?

I hope you can give some answers to the many questions, there is no doubt a picture saves a thousand words

Regards Oldtimer

[Martec]

Hi Phil,

The lock is in bits beside my chair (scruff room) and in answer to your questions:-

The lock is a completely assembly of door latch, opening and locking mechanism, motor, gears and micro switches, plastic moulding clipped to a steel base. It separates into 3 pieces, the steel and plastic lower piece with the latch (holds the door shut) with steel linkages to lock and open the door. The plastic moulding with wire traces moulded and insulated by the plastic and the 3 micro switches. Then the motor and gear unit, this has the small motor with an archimedial screw on the spindle driving a nylon gear which then drives the large gear with a cam on it.

The door latch hits the internal micro switch as the door closes and so the Rear Electronic Control Module knows the door is shut and so the lights can dim and go out (they go out anyway after about 20 minutes to save the battery.

The other two micro switches are purely to stop and redirect the power to the motor, but the RECM must reverse the current to lock and unlock the door.

Double lock is just a further movement on from Lock, basically the motor winds around moving the links so that the external door handle is disconnected from the latch, but the internal handle can still unlock and open the door (smash the window and open it as Mike did). By pressing the remote twice then it is 'Double locked', this means the motor winds a bit further and engages a pawl arrangement that also disengages the internal door handle (scary) and no chance of you or anyone else getting the door open other than a tin opener. Press open and the motor reverses and winds back moving the links to engage the internal and external door handles.

The 5 wires to the rear lock and the 7 (I think) to the passenger front lock and 11or so to the drivers door lock are all separately colour coded and wired via the central door locking unit and the remote unit to the RECM. The drivers rear door lock has two black wires with a yellow and green trace to the door lock switch and yellow and white wires to the motor switches.

Is the micro switch removable, with difficulty. I'll try and put pictures up later.

Brian

[oldtimer]

Gosh,
Thanks
P

[Martec]

Hi,

I've hopefully attached 3 pictures of the lock to show its guts, the middle micro switch is the duff one.

Brian

[Martec]

Sorry the pictures are not clear enough to appreciate how small these micro switches are, 15.3mm long (my camera will not focus on the switch).

I have been searching online for 2 weeks for similar switches only to realise they are an odd size, most seem to be either 20mm or 13mm long. I finally managed to read 'Cherry' on the switch with a back lit magnifying glass. I finally found the switch here

http://www.cherrycorp.com/english/switc ... led/dj.htm

I have tried a local Maplin store (no chance)

RS components and Farnell online catalogues, they sell Cherry micro switches, but not this one.

This is annoying me now so does anyone have access to 'Cherry's catalogue or know of a way to order a small number of switches from a supplier. Googling the part number Cherry DJ1GALAO doesn't bring up anything useful to me.

Just for cussedness I would like to find a way to repair this lock, as the only thing wrong with the lock is this $0.95 switch.

How big a problem is this, I have one electrically dead lock, how many do you have?

Brian

[Martec]

MOT Day!!

Last year the car had advisories for a power steering hose weep, since stopped,plus two rear brake pipes corroded which I cleaned up, etch primed and undersealed.

This time all 4 wheel pipes are corroded and the long chassis ones with advisories, but what was going to fail it was the rear passenger door double locked. working the fob buttons opened it and he accepted that and of course it doesn't lock now.

So when I have time its all new cunifer pipes and the locks will definitely be coming out, new sub-micro switches (one done) and the bit for double locking removed(filed off).

How annoying is that almost a fail due to a crap micro switch, emissions and main electronics great just a daft door lock.

Does anyone know where I can get an equally knackered rear passenger door lock cheap to modify and repair, please.

Brian

[J44EAG]

Regret to say I simply don`t have the patience to muck about with defective parts. With so many of our cars in breakers yards, it is far easier for me to find a secondhand part for just a few quid.

My first port of call for new or secondhand items would be dear old Neville Anderson at North East Jag Spares followed by Eurojag. Then there is ebay but a degree of caution needs to be applied.

When something falls off J44, I need a quick and hassle free answer and for me, the least time spent with the car in bits, so much the better. I also go scats if I have to do a job twice and have to replace a repaired part which then fails after a repair. ie dodgy solenoids which may be on their final movements.

Yes, I know repairs can work well. In my case, my tenacity and determination has disappeared. Fair play to those of you that can and do beat this type of problem into submission.

Mike the grumpy old git.

[Martec]

Hi Grumpy,

Nice to hear from you again. The reason I want to fit repaired parts is that a working second hand item maybe on its last legs. The problem door lock was perfect a year ago and the one that is only operable by hand was iffy last year.

With the help of Jack (electronics engineer) I'm trying to find out what is causing the problem and a more permanent fix for the future. The only one I've worked on had corroded and stiff pivots so a clean up and graphite grease may help and a water guard. Its possible the stiffness caused a higher current draw and so burnt or worn out contacts.

I can appreciate that you Mike and others use it as an everyday car but for me it is a toy (5000 miles last year, the MKII never made that).

How's the floating workshop coming on?

Brian

[J44EAG]

Floating workshop sunk.

No problem though. Pumped out, sealed and going again. Pretty routine occurrence. Snap together floor fitted for £10 from local dump and genuine nylon Persian flying carpet installed. Amazing what you can find in a yard skip.

Washing machine, tumbler and fibre glass repair centre up and running again and whole project now £27 in credit over and above what I paid for the floating heap.

Back to the thread. It is great that some of us have the tenacity and interest to explore common items such as door locks. It is all good stuff. Regret to say that I am struggling health wise so I`m not able to get in close to these subjects as I used to be. Please keep up thee good wok. MUCH APPRECIATED.

mike

[Martec]

Hi Mike,

Sorry to hear of your health problems, I hope things improve soon.

Something that might be of interest to others, I've had the car a year and I'm getting quotes for re-insuring it. It is on a JEC policy with P James as are the other two toys in my name, I have over 20 years with classic policies in my name and no moderns, so no 'no-claims years.

I thought that the P James/JEC policy was a moderns policy and so I had I years no-claims, but it is a 'specialist policy' (as it is over 8 years old), it has an agreed value of 2p ish and if I go else ware then I can claim 1 year no-claims. I only but 4500 miles on it but have covered 5000 miles!!!! but to cover it for 6000 miles puts the price up by 40%. We will probably stay with the original insurance and share the driving fun with the MkII.

Brian

[dhdove]

"it has an agreed value of 2p ish"

I knew S-Types were cheap but surely......?

TonyS

[Martec]

After 5 cars repaired and MOTed I had a day to myself so started on the rear drivers side door lock. The repaired door lock was opened up and the claw that acts as part of the dead lock arrangement was sawn off (It'll not lock me out again!) reassembled and then to remove the old lock.

On Rogers spares car we had to dismantle the whole door to get it out, but with that lock in front of me I managed to separate the plastic handle bit from the door lock part inside the door and it all fell out of position into the bottom of the door.

Refitting the repaired lock and existing door handle was not easy, 3 times it was in and out until finally it was in correctly and the nut and 2 screws refitted to secure it all together. So yes they can be removed for replacement and without dismantling the door but I started at 11am and finished at 9pm. I doubt it will be easier next time either, a few lessons have been learnt and no blood loss this time.

Brian

[Martec]

I seems to make a habit of talking rubbish! Yesterday I took the other rear door lock out, opened it up and cut off the deadlock hook and it is now ready for Jack Franks to fit new micro switches.

To remove and open up the lock and cut off the hook took less than 2 hours. From the previous experience I am looking at less than a few hours to refit it after repair.

Brian

[Martec]

Update for those interested, I now have all 4 door locks working electrically, the deadlock hook inside the 3 passenger locks have been cut off so it can't lock me out again, the key in the driver's door lock appears to mechanically override that lock.

I have refined the removal and refitting procedure of the rear locks and it is down to 3.5 hours, 2.5 hours if you ignore one of the self tapers. The front passenger lock came out, striped, modified and refitted in less than 1.5 hours. I left the driver's door as the key overrides the deadlock.

Also the door card will come off with the door shut, gently pull the top until it come away (having removed the cup around the interior door levers and the two screws in the centre of the door).

So now I test it to see how well the replacement micro switches last.

Best wishes

Brian