Tailgate lock again!

53 plate TD4 Sport 3dr

Im pulling my hair (not that I have much) I have run out of ideas on this problem, Ive read all the threads here regarding the tail gate lock and door not opening. (Which have been excellent to get me to this stage) I have successfully got inside the car and removed the boot panel, getting the door open that way, changed the actuator lock and mechanism, checked the cables back to the relays in the rear offside quarter, even fitted a new tailgate handle. But still the damn thing won’t operate on the fob, handle or internal switch. The CL on the front doors work fine, the rear window and wiper works normally.

simply nothing happening with the tailgate lock, no action from the micro switch (springs ok) or the lock itself, any ideas sensible or otherwise would be very welcome".............

Thanks
Graeme

You can hear if the handle micro-switch is working, as it makes a faint click when release flap is pulled. If the micro-switch fails or it's wiring is faulty, the door won't release.
Does the window drop, when the handle flap is pulled?
The lock on the rear handle is for winding the rear window up. The rear window can be made to drop fully by keeping the unlock button on the fob pressed for 3 seconds.

when I operate the tailgate handle There is nothing happening with the micro switch, no click and no movement of the window.
But the window will work on the fob and cabin switch, so it’s lock related, I’m wondering if I need to do some sort of reset when I fitted the new handle/microswitch

It’s really stumped me, there are so many threads on the subject but I can’t seem to find the solution.

Hi have tried to lift the door as some time when the boo toms hinge is warn it affects the lock just saying as my 2004 td4 used to do it till I put new bottom hinge on

That should have said have you tried
To lift the door as some times when thebottom hinge is worn and it affects the door opening (stupid predictive text)

I’ll give anything a go now, checked that, all the doors are closing correctly, no warning lights on, so no problem in that area, even hard the hardtop off to check the sensor there, that was Ok too. It’s odd as it happened all of a sudden the wife said she heard a strange noise in the back somewhere , then after a short journey could not open the tailgate.

Lock, and actuator replaced, new handle fitted, wiring seems to be oK what else is there!!!!

Nysensi said:

when I operate the tailgate handle There is nothing happening with the micro switch, no click and no movement of the window.
But the window will work

Click to expand...

That suggests the micro-switch isn't working, so nothing will happen.

The tailgate lock gets its feed from the CCU - there is no separate fuse for the tailgate and so if all other door locks work then it can only be the microswitch not operating - maybe a broken tab on the door handle or a broken wire / connector on on the feed or to earth. I think my next step would be to check that there is a black earth connection (and it is connected to earth) to one side of the switch and that when you operate the tailgate catch it puts an earth on the other contact of the switch - this is a black / orange wire on my diagram (up to 2003) so it may be different on yours. If this works then the CCU is not sending a signal to the lock. This may be due to a broken wire or connector - purple / blue on my diagram or it may be a legitimate reason, window sensor or something else that would prevent an 'unlock command' - can't think of anything other than the window at the moment !

You can put a voltmeter on the feed to the tailgate lock and see if the CCU is sending a signal.

These faults can be annoying, mine did the same last week but that was a window sensor fault and the CCU didn't know where the window was - but the window didn't work on the switch or fob in this case.

Andy thanks, it’s a new microswitch, so it must be the cabling, I’m no expert with the meter, but I will try and work through your guidance thanks.
When I find a solution to this one, I’m going to make sure its shared for all, this is such a pain, I’ve been messing with it all day, not much daylight left now.

As Nodge has identified, is the handle actually operating the microswitch - you will hear a 'non-electronic' click from the switch - it is simply the switch operating not a relay. If nothing then start here - a meter will help as you can check the earth and the switch ! good luck................

Andy, the microswitch is not activating, it’s brand new, so going to start with a thorough Earth check first, thanks for the tips, fingers crossed.

The wiring colour codes appear to be the same, the purple\black going to the lock actuator is giving a .25v blip as the CL is activated, the orange black going to the handle is giving a steady 1.25v with an brief increase to 1.55 when the CL is operated, earths clean and strong.
So does this suggest CCU fault?

I’m going to have to leave the job now till next weekend, work is dragging me away, I keep thinking about the post that starts with eureka problem solved, I hope that’s not too far away

Nysensi said:

Andy, the microswitch is not activating, it’s brand new, so going to start with a thorough Earth check first, thanks for the tips, fingers crossed

Click to expand...

Your best bet is to remove the door handle or the release flap and physically check the flap is moving the micro-switch. If it is, then you'll hear the switch contacts snap closed then the flap is operated. No faint click suggest a duff micro-switch. You can test the electronics and wiring by bridging across the micro-switch contacts. This will bypass the micro-switch and if everything else is working, the door release should activate, even if the door is open.

Thanks again Nodge, I’ll try bridging the microswitch, but being as it’s brand new, i hope that it’s not the problem, their is going to be a simple answer to this, it will be solved, ...eventually.........I’m sure.

Back on the case again this weekend,
update, I have run a diagnostic check with an obd2 reader, no codes reported, so I guess that’s good. Running some checks the voltages, the orange brown feed to the new tailgate handle microswitch is taking a constant 1.4v. Tried bridging the switch no activation of the switch (clicking) at all,

Checked the feed to the CL actuator which gets the requisite .0.4v blip when the remote is operated, so I feel that’s correct.

I’m now convinced the fault is between the CCU and the switch, cables and fuses are good. Does anybody know if the 1.2v constant to the micro switch is correct?

Problem solved!!!!! It turned out to be a small cluster of earth wires in the centre of the tailgate loom, where 5 become 2 heavier gauge. The earth from the microswitch into this connector, was loose. So simple in the end, made good the connector and eureka, all working normally again.

I guess the moral of the story is check, check and double check all cables and connectors, looking for the elusive weak link! Thanks for the inputs taking me in the right direction. The good news here is that I have a brand new tailgate handle, so hopefully no problems there in the future.

Is there a way to make a manual by-pass in case of any future problems?

See my post 22nd Sept !!!

I tried Andyfreelandy bridging plan, but the broken earth connection in my case defeated that solution. My earth checks were initally at the earth point in the offside rear quarter, but i had not reliased there were interconnectors along the route. In hind sight there is not much too the system,, the actuator and lock, fuses and the dreaded micoswitch in the tailgate handle, so once you have checked those things and proven you have a supply, it only leaves cabling, it took a while to work that out, but thinking i had checked it, i went back over it 3 times before i found that dodgy connection.