Thread: Rear door not unlocking with central locking

Originally Posted by BushDisco

Cheers Brad, I'm an electrical engineer by trade so if it comes to this I'll document in a write up. Appreciate the response and advise.

I didn't know Electrical Engineers had a trade (My father holds that qualification also)

I'm an electronic technician "by trade", which these days means I'm qualified to repair VCR's and CRT's. So I'm thoroughly obsolete.

I use a hardened pick to pop the swaging on the case (ground from 3/32 tool steel lathe blanks because I damaged a few screwdrivers abusing them for this initially), then tap the shaft at the front which works the bell loose over whatever grungy bit of swage was left. A cautious wiggle gets the brushes over the end of the commutator. The whole lot gets hosed out with isopropyl alcohol in an aerosol can until there is no trace of carbon left. The commutator cleaned up if required (rarely more than a good wipe with an alcohol soaked cloth). The sintered bush in the casing gets some ISO32 Royal Purple synthetic oil and the nylon bell gets some Electrolube SPG (Special Plastics Grease). Probably both over the top, but I have them handy for other stuff. Actually, the SPG is magic for anything where metal and/or plastic is involved.

I've not had to replace or remediate a brush yet. Just a lot of cleaning and care. Re-assembly in the reverse, but use of a dental pick to separate the brushes. Test with a bench power supply and re-swage with a screwdriver and calibrated hammer.

There are 2 motors in the lock. The lock motor and the super-lock motor. I've not seen a failed super-lock motor yet in either LR or VW. The lock motors do tend to work hard.
Replacement motors are available (they are all Mabuchi or equivalent) and model suppliers have gear puller kits designed for helis which enable you to remove and replace the worm gear on a spare motor if required. The shaft length is the critical bit, but as the youtube dude demonstrates, you can always just replace the brush-end.

While I haven't seen it, apparently the superlock motor is a major failure point in the VW's and results in one of two options. A 50mm hole saw to the outer door skin, or a 50mm hole saw to the inner door skin. Lucky for me I've found loads of pounding heavily on the door while repeatedly pressing the button eventually gets it open.

Best of luck. The front passenger lock motor was the first thing to go on my car (2 days after I picked it up). It had the good humour to lock out my mother-in-law, so I forgave it.

If you are anything like the Electrical Engineer my old man is, you'll muck it in with a blindfold on.

Lol, I hope your mother in-law had a sense of humour!

I trained in both electrical and electronics, started work in the early 90s in the UK with electrical machinery (large electrical motors and such), before moving into more of my passion area which was digital circuits, PCB etc. then emigrated to Australia in 94 and like you found electrical work scarce so retrained in computer management (called ICT these days) and never looked back. I’m lucky I found a booming industry quite early on and even though fresh to the field I managed to learn from the ground up over the last 26 years as technology has advanced.

like everything life is a series of choices and luck I find is retrospectively random.

anyhoo I’ll be taking a look at that lock today so will report back findings. Thanks for the detailed instructions.

Ok, so yesterday I removed the locking and actuator mechanism, disassembled, stripped the motor (was filthy inside as had been predicted), greased all gears and reassembled. Connected back to loom on car without installing in the door and using the remote I locked and unlocked doors and saw and heard the locking actuator working on the rebuilt RLH unit. Good I thought.

Bolted back into disco, then realised I couldn’t attach the second wiring plug with the actuator installed, removed, fitted both plugs this time (it was late, I was hungry and probably rushing a little at this point) and tested again. With the door open still I could hear solid clunks, see cable movement etc so I thought all good.

Final test was with the door closed. So closed door, locked, unlocked..... oh oh.. door will not open. Tried outside handle, inside cable, nada..

So here I am, Saturday morning cup day. Heavy rain trying to unlock the RLH door. I’m guessing somehow it’s super locked as even the cables will not release. All other doors operating ok.

ok brains trust, ideas?

Originally Posted by BushDisco

ok brains trust, ideas?

Oh that doesn't sound good.
Lots of thing to try in no particular order based on old wives tales and anecdotal writeups.
- Get an assistant to repeatedly try and lock/unlock the car with the remote while you pound on the door.
- Hard reset the car
- Try to lock/unlock the car repeatedly while simultaneously manipulating both internal and external handles

I can vouch for the first one working on Veedubs. Haven't had it happen on the LR.

One thing that might be worth trying is if you can figure out where to get access to the other end of the loom going to the lock and manually drive the motors with a battery.

Probably a bit late and of little help right now, but I *always* test the full range of lock functions by closing the latch and activating any door switches before doing a "door closed" test.

There are some writeups on disco3.co.uk on getting a front door internal skin off with the door locked. Something like that might be possible on the rear door.

I didn’t get as far as outing the window winder or door card back on so I still have access to the locking mechanism from inside the car lying down in the back seat. I’ve also been able to remove external handle again and I have access to the cable operated lever on the lock that you use to open the door from the outside, I can manipulate the lever but this does not open the door.

I can lock and unlock the doors and the servo definitely clinks in a ‘normal’ fashion and seems to operate correctly. It’s just the door will not open.

ive tried pounding on the inside and outside whilst repeatedly locking and unlocking.

one small positive of this exercise is I found an old 50 cent coin, quite corroded and wedged down next to the puddle lamp. I’ve heard a rattle in the rear of the car for a long time and have not opened the door card up since purchased so it’s been there a long time!

So I resorted to ignoring logic.. from inside the disco with the door card removed I was able to operate the unlock lever. With the locks ‘locked’ still could not open. So tried with the locks in the locked position. Bingo door opened straight away.

ill now dismantle the lot and try figure out what went wrong.

not the way I was planning to spend today. But at least the door is open now.

thanks for help brains trust, I’ll post again when it’s working correctly.

Originally Posted by BushDisco

So I resorted to ignoring logic.. from inside the disco with the door card removed I was able to operate the unlock lever. With the locks ‘locked’ still could not open. So tried with the locks in the locked position. Bingo door opened straight away.

ill now dismantle the lot and try figure out what went wrong.

not the way I was planning to spend today. But at least the door is open now.

thanks for help brains trust, I’ll post again when it’s working correctly.

Whew! Nice work.

Still not quite right.

So I pulled out the full mechanism and saw where the issue was, one of the levers on the mechanism was on the incorrect side of a spring, allowing the door to lock, but not unlock even though the actuators are now working correctly.

Fixed and reassembled, now the door locks, unlocks and I can open manually from inside and out using cables / handles.

One last issue remaining, close the door, lock it using remote- can't then open using outside handle. The lock mechanism works, it remote unlocks and also unlocks using hand sensor built into handle, but the door will not open using outside handle.

When I reach in and pull inside cable (I've not yet reattached the inside handle) the door opens easily. I can also sit inside car, remote or manual lock and remote or manual (pulling cable) unlock.

Finally once unlocked the external handle can be used normally to open the door from the outside.

But when I lock the door and try to open from outside then even after unlocking i can't open the door using the extremal handle.