2008 Expression Estate rear door conundrum

[brianronald123]

Hi. I've seen various forums discussing the problem of a tailgate not opening, but I seem to have the opposite - I'll describe the rather odd symptoms, if anyone has experinced anything simlar I'd be pleased for some advice:
About 2 weeks ago I had a problem with the tailgate NOT opening either by keyswitch or the door sensor. Having had this problem last year I had already changed both the locking mechanism and door switch with original Renault parts and was hoping (and thought it unlikely) that the same problem had not occured. I opened the door manually from inside, and found that the switch was indeed trying to operate the lock release, it just lacked the 'strength' to operate the lock when the door was closed....suspicious, I thought. So, I proceeded to give the lock and catch some lubrication with WD40 and some grease and was happy that I'd solved the problem as all seemed well......
Around the same time (and this may or may not be relevant) I had to remove and replace the rear wiper arm and blade. Natually this involved some complication, the usual hassle of the old plastic arm casing being broken away to reveal the rusty corroded-on bush, which had to be cut before levering it off etc.... again, mission accomplished.

Here's where it gets weird - two days ago (a cold, rainy day) the rear wiper refused to operate from being turned on by its lever switch on the steering column. Bizarrely, I noticed that when I also switched on the rear demister, it didn't work but the wiper DID. And then, just to confuse things further, the rear door opened BY ITSELF, while i was driving along! Luckily, the door did not swing open and nothing was lost from the rear of the car but I did have to make an emergency stop, get out and close the door before continuing. This happened another three times on my journey (before it occured to me to use the manual central door lock button on the dashboard!)
I've since discovered that now every time I start the engine, the rear door catch releases automatically. Worrying! Especially if I forget to do the 'manual locking' thing before pulling away!
Help! any ideas?

[almcgrail]

Check for broken wires in the loom from tailgate to car body when boot is open wide.

[brianronald123]

Thanks for the tip - sadly, no help really. I had a good look behind the door panel and inspected the wiring loom around the hinge area and could find nothing untoward, nothing broken, unplugged, corroded.
I have discovered thaat there is some sort of electronic link between the door handle switch and the rear wiper motor, in that when pushing the switch there is some momentary movement from the wiper (?!)
I've read that removing then fuse box and cleaning the circuit boards and multi pin connectors might help, but where exactly is the fuse box on this model? I can see under the bonnet next to the battery a triangular cover which exposes some ciruitry and the 'heavy' fuses (40, 50 amp etc) - is the rectangular plastic box situated above it the fuse box? How are you supposed to access that? There's only about an inch of space to work in - has the battery, ECU and other bits and pieces got to be disconnected first?
Having already had such fun replacing the headlight bulb earlier (90 minutes! Cuts, bruises and colourful language a-plenty!), do you think it would be an idea if we all club together and get the designer of this model a guide dog? LOL!

Seriously though, if anyone can pint me toward a diagram, video on Youtube, downloadable manual I'd appreciate it. It's a 2008 model Expression Estate, 1.6 petrol

[noelo]

It is one or more breaks in the wiring loom
Where the loom bends with the opening
And closing of the tailgate, the outer
Insulation may look intact,but the copper
Strands are broken inside. I had the exact
Symptoms

[AlexB]

Demister-wiper "cooperation" may be caused by a broken earth circuit, in theory... It can be in the loom or a separate wire. At this point my experience with the tailgate stops, never had problems with it.