Tailgate wont open?

[jnoam]

Hi everyone,
I have a 2004 Megane 2 1.6l manual, 5 door version, not "handsfree". Since a few months ago the tailgate refuses to open.
Mechanically its all perfect, when I open manualy (using the small white plastic thing on the lock, from the inside of the boot) it works OK. but pushing the button does nothing.
I checked the motor feeding it with 12V, it works OK. Just to be sure I replaced the lock mechanism with a working one from another car - will not work. I checked the switch - works OK. My dealer tells me this is probably a breakage in the computer PCB and that I should replace it (about 1000 pounds here); so I wanted to ask if anyone had such a problem before or can recommend a diagnostic measure? does anyone know the connections map between the computer and the tailgate lock?
if worst comes to worst, can I simply connect the lock to the rear lights and solve the problem?

Thanks anyone who can help, and everyone who reads!

Jonathan

[cactusbob]

The tailgate opening button is just a simple switch.

Check the connector on the opening motor:

Track 1: Motor supply
Track 2: Motor supply
Track 3: Opening Signal
Track 4: Earth

[jnoam]

Hi,
Thanks for the response.
I checked this; I get the ground OK and track 3 is also OK if I understand correctly - it seems to be related to the microswitch internal to the lock mechanism; on the motor signals I am getting weird response:
1. Pin #1 is coming directly from the locking switch - and the wires and the switch perform as expected
2. checking with a voltmeter I am getting strange responses. There is no real potential difference between pins 1 and 2, changing somewhat when the switch is pressed but not much (mVolts at best). Between both and the ground there is appx. 1-1.5V difference, and fluctuating, seems mostly like noise.

Any ideas? have anyone heard about the HCU (the computer on the dash left side) being broken in the PCB? is this frequent?

Thanks
Jonathan

[cactusbob]

I can't imagine it's that clever to be honest with you.

I'm not sure how the door motor knows when it is allowed to open. I guess that it receives a signal from the UCH, then it allows the button to work.

One of those pins should be from the UCH you need to check the signal on that when the car is locked or unlocked. Off the top of my head does it make a noise when you press the unlock button on the card? It may be a two position motor, one position would make it "openable" for when the release button on the tailgate is actually pressed.

Makes me think of a cool mod, I wonder if it can be wired so that when the button on the card is pressed it actually pops the tailgate.

[lovol]

I know this is a 'really' old thread, but I've now the same problem, so was wondering if you ever solved this?

[jnoam]

Well, not really. I have a workaround - I connected the lock mechanism to the rear lights, and so whenever the lights are on the tailgate would not be locked. But I can live with it and it costed me an hour of work and about 5$ in parts. I don't remember exactly what was the circuit - I think it included a relay - but it was VERY simple (and worked on the first attempt).

[Pritch558]

My boot wont open at the moment (bought it nearly 2 weeks ago, worked when bought, hasn't worked for about a week or so), I've found the fault in mine is a loose wire in the rubber housing (left hand side of boot near boot arm when open), i've got mine booked in with a local auto electrician on Monday to get sorted.
Could probably do it myself but with it being my new toy, I figured i'd let the professionals sort it first

[lovol]

Thanks for your replies.

Wow jnoam, what an ingenious solution!

Pritch558, I suppose it depends on what your more confident with. Myself, I haven’t a clue about cars (I’m a software developer!) however, I can do electrics and quite like taking things apart. And since it’s our 2nd car, not essential everything works, so thought I’d give it a go.

I fixed it!

Fortunately it was only water in the button that you use to open the boot.

So for other’s benefit. I just got a flat screwdriver (small one) and prised the button off the car. It popped off REALLY easily. Then used some very small long nose plier to pull the other part of plastic through the hole. Then used the same screwdriver to prise the 2 parts (that are still attached to the car) apart so you end up looking at three parts. 1, rubber button with a spring on it. 2, micro switch with connector, 3. Connector (attached to the car with 2 wires, blue and brown).

Anyway, the micro switch looked perfectly undamaged. However putting a multi meter on it showed some resistance (i.e. a slight connection) even when not pressing the button.

5 mins with a hairdryer and it was working perfectly again.

Cleaned rubber parts on button.

Put parts 1+2 together, then attach to part 3. Then push back into car (hole). Done

Any bets on how long it will last?

[freelanderuk]

well done , and saved a few quid

[Bertisport]

Hi EVeryone,

I've got the opposite problem, my boot occasionally refuses to latch and stay shut.... when I go to close it it will just bounce off the sticker.

Weirdly this started not long after I had someone at a set of trafficlights that my number plate light wasn't working. Add to that my rear screen heater and wiper have NEVER worked

I wondered if it was the loom, sure enough when I wiggle the rubber gaiter on drivers left of the tailgate the number plate lighhts will work (if i have the lights on) and the boot will latch.

Does anyone know if the tailgate loom section is an individual section? and does it connect in the car or in the tailgate? I've tried to find out off the wiring diagrams but I can't figure it out

Cheers

[freelanderuk]

You will have to open the covering on the loom and repair the split wires .there are a few post on here about broken wire in that part of the loom

[almcgrail]

Defo check the wires from the hatch when open. Piece the wires in to extend them, or you may have the same problem in the future. I also had many broken wires, number plate light, wiper, rear screen, but it wasn't until lock went I got off my arse to sort things! Good luck.