2007 ML63 - Power Tailgate Not Closing

[E55BOF]

My newly-acquired Japanese import 2007 ML has a tailgate problem. It unlocks and opens fine, whether door switch or key fob is used, but will not close. Nothing happens when you press the button on the key fob, there's no light in the closing switch on the door, and nothing happens when you press it.

Closing it manually, there's considerable resistance to movement, so you have to take it gently to allow the pressure in the ram/s (not sure whether one or two) to bleed away, and when you do get it closed, the electric pull-in lock doesn't operate. and it won't close fully. In that position you then can't open it without using either the keyfob or the in-car unlock switch. Just to be awkward, occasionally, after fiddling with the opening switch in the car, and the switch on the key fob, it will fully close manually.

The electric pull-in never operates.

The importer has thrown money at it - new SAM, new pump, new support struts - but it's not fixed.

I've had the iCarsoft on it, and the pinch strips, which I thought might be the problem, are fault-free. However, I did get a current and stored fault code for 'rear door locking lever position implausible', or words to that effect (the iCarsoft won't talk to my computer...).

I'm inclined to suspect that that's the source of the problem; most likely a dodgy microswitch in the handle mechanism, and if the system thinks the lock is already in the closed position, it won't move the tailgate. That's my best guess, anyway...

Does anybody know better? Any other ideas? Has anybody had the same problem? If so, how did you fix it?

 

[Bobby Dazzler]

A few things to try.

Check that the release lever (behind the chrome strip above the rear number plate) is not stuck in the open position. They often stick in the open position which stops the whole boot mechanism working.

Apply just a little pressure to the open tailgate so that it drops by say quarter of an inch before trying the button on the tailgate, key fob or driver’s door. Try again at half an inch and one inch.

Try swapping the boot release switch from your other ML and other parts as necessary until you work out which part makes the difference and it all springs into life.

 

[E55BOF]

No, the release lever isn't stuck; quite the opposite - it's not apparently connected to anything... 'Rear door locking lever position implausible'? I'd say that's very probably it.

It won't release the tailgate mechanical lock in any circumstance, and if I manually close the lock with a screwdriver shank in it, it won't even open it then. I hadn't checked it out until your post jogged my memory, so thank you very much. Looking hopeful...

I'm not going to start dismantling and swapping bits around the cars; the blue one's going in to Terry Gates a week on Tuesday anyway, and if its sorted before then, the convertible needs a service now so it can have the slot instead.

 

[Jobsworth]

I think the fact there is no electric pull-in when it clicks into the latch might be the clue. I think it relies on a switch in the latch to decide if the tailgate is open or closed. If it can’t see it’s open it probably won’t close on the button or pull the latch in when it contacts. It’s a hunch. I have changed a lot of latches for water ingress in my time

 

[E55BOF]

I presume by latch you mean the lock unit, A 211 740 02 35, which on mine (807 MY) it shares with the W211? If so, that all makes complete sense, and is very helpful.

However, if the 7Zap diagram I'm using is correct, there is an electrical connection to the handle as well. However, the fact that the part numbers for the handle assembly (A 164 740 04 93 on mine) don't differentiate between powered and manual tailgates may mean that's a red herring here, but if so, what's that connection for?

If you've had to change the latches in the past, that seems like the best place to start. I think I'll just have to try a little diagnosis by substitution. Pattern parts are plentiful and cheap on Ebay, so it won't cost much even if it doesn't solve the problem. The worst bit is, I'll have to take the tailgate trim panel off to get at it, and it's a bugger to put back if you're working alone, as I am.

Could I ask, what were the symptoms of the problem when the latches needed changing?

 

[Jobsworth]

I presume by latch you mean the lock unit, A 211 740 02 35, which on mine (807 MY) it shares with the W211? If so, that all makes complete sense, and is very helpful.

However, if the 7Zap diagram I'm using is correct, there is an electrical connection to the handle as well. However, the fact that the part numbers for the handle assembly (A 164 740 04 93 on mine) don't differentiate between powered and manual tailgates may mean that's a red herring here, but if so, what's that connection for?

If you've had to change the latches in the past, that seems like the best place to start. I think I'll just have to try a little diagnosis by substitution. Pattern parts are plentiful and cheap on Ebay, so it won't cost much even if it doesn't solve the problem. The worst bit is, I'll have to take the tailgate trim panel off to get at it, and it's a bugger to put back if you're working alone, as I am.

Could I ask, what were the symptoms of the problem when the latches needed changing?

Usually not working at all. Have to climb in the back to open the tailgate. See them sometimes where they open but don’t electrically pull down. People get by slamming them hard to latch, but they don’t last long treated like that. Water leaks in the high level brake light and drops straight into the plug.

 

[E55BOF]

Thank you for that, and for your time.

Time to get the trim tools out tomorrow...

 

[E55BOF]

Woke up this morning and a penny had dropped in the night... The handle moves with no resistance, so it's not pulling on anything now, so either the linkage cable is broken or detached, or it or a part of the gubbins inside the latch has seized in the fully open position. I know the actual latch hasn't. More anon...

 

[E55BOF]

Somebody who didn't know what they were doing has been in there; the main trim panel fell out on to my head as soon as I removed the second window side trim piece...

How do I know he didn't know what he was doing? The handle electrical connection is to a microswitch; not working, replacement from main dealer here tomorrow, half the price of Ebay.

That's the handle (easy, cheap) part of the problem solved. Now for the lock/latch assembly...

 

[E55BOF]

Not the lock/latch; when I removed it, it was a brand new pattern part. I wish the vendor had told me he had had that replaced... I'd already bought one (pattern part too), so I fitted that. No change...

Replaced the handle microswitch; no change..

I took this lot off the iCarsoft (photos, because my computer won't talk to it...):


The door handle switch was disconnected throughout, but connecting it up made no difference. It doesn't work anyway, and wasn't operated at any point.

The hydraulic pump doesn't appear to run at all; on unlocking the tailgate with either the in-car switch or the key, the lock releases, but nothing else happens. The tailgate lifts very well with just the support struts (I took them off and it never budged when unlocked), just like on my black one, which has a manual tailgate. (I'm beginning to wish this one did...) It latches closed manually, but the electric pull-in doesn't happen.

I think this indicates the problem must lie with the Rear End Door Closing Control Module, from which came the datastream. I'd never heard of it until the iCarsoft brought it up. I can't think of anything else it could be, really; everything else has been replaced...

Does anybody have any thoughts (other than 'Thank Goodness it's not me'... )?

 

[Jobsworth]

I have converted a few to manual operation when water ingress has destroyed the pump unit. It involves removing the ram, sealing the hole and changing the gas struts to ordinary type. Also unbolting something from the offside hinge iirc. After that they usually just work as basic type, but the electric pull down latch should be working already. That concerns me slightly. Wiring plug isn’t green?

 

[E55BOF]

Thanks for that. No corrosion anywhere; it's all as you'd expect from a car with only 35K miles on it that has been garaged all its life.

Would the fact that the system thinks the rear door handle is permanently held open not inhibit the pull-down latch?

 

[Jobsworth]

Possibly, but if it was unplugged… not sure.
Can you borrow one from other car?

 

[E55BOF]

I've fitted a new OE microswitch, and tried the handle both plugged and unplugged; same fault as with the old, faulty, microswitch -it does nothing at any time.

Do you know where the module is actually located, by the way? The internet says it's in the tailgate, but it definitely isn't; or if it is, I can't find it...

 

[Jobsworth]

The hydraulic open/close module is hard against the rear panel. Need to take the spare wheel and bits out to see it. It’s not responsible for the latch though. I’m sure that comes via the rear SAM, but I’d have to check and I’m shut on Thursdays

 

[Jobsworth]

I don’t need to check, it is from the rear SAM. I’m sure.

 

[E55BOF]

Thank you very much for that; I thought I was going mad - I use a parts finder called 7Zap, and the image is plainly wrong. By sheer good luck, there's somebody on Ebay with the correct part not far from me, so I'll be up there post haste just as soon as they get back to me.

 

[Jobsworth]

You say the SAM has already been replaced. I would check it’s coded correctly.

 

[Alps]

Check the wiring where the boot lid hinges are, most likely the wire has broken. tell tail for this is the lack of a light on the switch.

 

[E55BOF]

You say the SAM has already been replaced. I would check it’s coded correctly.

Car's going in to Terry Gates on Tuesday; I'm sure he will do that. The iCarsoft finds no fault codes, though.

Check the wiring where the boot lid hinges are, most likely the wire has broken. tell tail for this is the lack of a light on the switch.

The switch doesn't light, so you may well be right, but I can't see that would account for the tailgate latch electric pull-down feature not working.

I've changed the Rear End Door Closing control module, using what was probably original rather than the later (but still correct) module the previous owner fitted, and some of the data stream has changed, but the fault is still there. I've come to the end of what I can do; time for a pro with a Star to have a go...