Grand C4 Picasso Tailgate lock

[Old-Guy]

It's broken! To be more precise, it's stopped working; we've only had the car 2 weeks. Parked the car this evening in the twilight, boot refuses to open; earlier in the afternoon, the tailgate 'handle' was a bit iffy in engaging the switch, - now the handle just rattles around and won't engage the switch.

I remember reading a comment somewhere about the C4 Picasso's notorious tailgate lock. The car's still under seller's warranty, but it's a 320 mile round-trip, so it makes more sense to ask them the pay for the parts if I fix it.

Can anyone tell me what the typical failure mode is please? What comes undone or breaks? In the latter case, it looks to be a choice between the plastic handle assembly (8726 V7) or switch (6554 ??). Is there any way to tell without dismantling the tailgate which version of the switch is likely to be fitted (service.citroen is unspecific despite quoting the VIN)?

[Old-Guy]

Supplementary question:
Does anyone have a wiring diagram for the boot lock please? If this is a common failure, I have a mind to fit an internal emergency switch wired in parallel with the OEM switch.

[RichardW]

If it's floppy, it's the handle - you way well find you can make it work by pushing the handle forwards then lifting it to trip the latch. They're pretty weak - ours has been broken ages, but we can still open the door by pushing the handle forwards. The trick to not breaking the new one is to not use it to lift the door - do it via the light rail adjacent to the switch instead. IIRC you have to take the door interior liner off, then the trim strip across the outside of the door (about 8 fiddly bolts on the inside) which then gives access to the lock fixings. This shows how; he repaired it but mine was definitely broken beyond help. I think it's just a 2 wire affair, so a simple piggy backed switch should do the trick if required.

[Old-Guy]

Thanks a lot, Richard - brilliant.

This afternoon, I threw the Green Lady's spare wheel and jack in the back of the Picasso and strapped it down securely - using the surplus (about 75%) length of the strap to make sure the spare couldn't move at all. I've read the section in the Handbook on how to release the tailgate in an emergency by tripping the lock mechanism from inside the boot with a small screwdriver. Guess where the strap ratchet and the knot are?

That's right, rear O/S corner between the spare and the tailgate!

Here's hoping your trick of pushing the handle forward will work tomorrow. Of course, there was a good reason for loading a spare - city centre appointment tomorrow morning and the car will be parked for several hours in a public car park. Just as well the row 2 seats tilt and slide easily and give access to the boot to stow coats out of sight.

A piggy-back switch is obviously necessary - as high as possible, and recessed; perhaps operated through a small hole. Have to give it some thought.

EDIT
I've given it some thought, but need to have a look in daylight tomorrow. Currently considering abandoning Citroen fragile design and aralditing the unlock handle solid with a small, waterproof, bush-mounting, momentary push switch fitted in it. To operate, grab hold of handle, push the tit, lift tailgate. Cost £nil as I have all the bits including brand-new switch with heavy-duty solid silver contacts - even a relay if conservative engineering demands. The alternative is to spend about £50 on Citroen parts that will fail in a few years. Shades of Xantia blower mod!

[Old-Guy]

What I didn't know when I bought the car was that a loose tailgate handle is broken and than very soon it will break off the operating pin on the relay.
The parts are expensive from Citroen:

• Sealed Switch (most Picassos) 6554ZZ £32.26
  Handle with unsealed switch 8726V7 £43.10

However, I found a Peugeot Citroen dealer selling a kit of handle fitted with sealed switch for £49.45 (including 1st class post). Not cheap, but still over £25 cheaper.

I didn't need to remove the tailgate trim completely: after undoing the 2 plastic rivets (either side of the latch), the T20 screws in the interior handles and un-popping the dozen green plastic trim-fasteners (big flat screwdriver wrapped in a layer of thick (Gorilla) gaffer tape, I could fairly easily slide both arms inside the tailgate and undo the 6 x M6 nuts that secure the plastic moulding (the brackets for two of these had broken off the main moulding - now glued back in place with generous fillets of Aradite).

Parts probably won't arrive until Tuesday but I can live with that. If I need to open the boot, I can operate the electric mechanism with a shorting link (aka paper-clip); quite secure as the circuit is only powered when the central locking is open.

[RichardW]

Ours has been broken a while; perhaps time I fixed it then!

[lexi]

That's the fixing started already Guy!

[Old-Guy]

The dealer from whom I bought the car has willingly agreed to pay for new handle and relay. Parts from Desira ordered through eBay on Wednesday afternoon, arrived this afternoon by 1st Class post. This Peugeot dealer very sensibly swaps out the square-body micro-switch (widely used on other models) for the round-bodied switch fitted on the vast majority of C4 Picassos.
When I removed the moulded-plastic trim/housing from the tailgate, I found two of the mounting brackets were broken off and a third was partially fractured. Incompetent design (over-thin sections and lack of web radii) compounded by poor quality control (gaps in some over-thin sections). I've re-fixed the broken-off brackets and beefed up the joints to the external body with Araldite, so hopefully no more brackets will break off.

Failed, but still attached, bracket

Copyright Old-Guy

Broken bracket 'welded' back-on with Araldite

Copyright Old-Guy

Handle plus switch installed in trim ready to refit (note weld on cracked bracket)

Copyright Old-Guy

On Saturday morning, I fitted the new switch to the handle, handle to the trim, then outside to test the switch (OK), refit the trim (no problems), thump the the plastic 'pop' fasteners back into place, play hunt the fasteners in the 3rd row seat wells then fit them. Under an hour all told.