Tailgate opening and closing problems ML

[CrustyClam]

Hi,

My tailgate has just started playing up this week. I'm having to either manually open or shut it in most cases. The latch mechanism is fine.

I've accessed the motor/pump housing to inspect it, doesn't look in great shape. I also noticed a slight dampness on the carpet and when lifted a tiny amount of water was present. Not sure if a new leak is present or if it's related to the leaks I had either side on the rear side windows (Resolved). To be sure I'll need to monitor. (Maybe rear tailgate light leak)

Current state the boot closes ok when tailgate button activated, but won't raise. However earlier today it opened ok by the motor/pump, but had to be hand shut. (Didn't hear motor engage)

The motor/pump can be heard on the YouTube, think it sound a bit iffy near the end. Hard to hear but a bit like when you suck the dregs out a glass with a straw.

Any thoughts?

 

[CrustyClam]

 

[CrustyClam]

 

[CrustyClam]

Well I cleaned one of plugs that connects to some kind of control unit with a pcb cleaner brush, and also applied a spray with some electrical contact cleaner. The plug looked like it hand a tiny bit of water creep corrosion. It came up clean afterwards but didn't help.

Could it be the fluid is a little low as shown in the above photo, it's just slightly below the + mark? (Is the right way to check, or should it be rotated 90 degrees) Would it be worth a topup?

I've noticed if I wait a bit between opening and shutting the tailgate then it works slightly better.

 

[CrustyClam]

Well not wanting to wait for advice (patience is a virtue- sadly I don't have) I've ordered some areoshell fluid 41 (15 quid delivered) and I am going to add a squirt or two into the reservoir. Ordered a 10ml pipette to add the fluid. Found another forum post with a PDF showing that for my year of w164 the above photo is correct way to measure level.

It's the simplest and cheapest thing I can do, failing this I may just get it booked in as I don't have the necessary experience to judge what to change next. (Or decent diagnosis equipment)

Will update post once I have a resolve hopefully it will be of use to others in the future.

 

[Steve@Avantgarde]

I would check the seals around the rear lights and the 3rd stop lamp, its likely water is ingressing through one of those, and yes it will take out the closing tailgate module. Might be worth buying the wiring plug and connectors and repining that first to see if its just a rotten connection, but I highly suspect the unit has failed.

Once you have repined it you could ask a specialist to check the actual values of the closing module.

 

[CrustyClam]

I would check the seals around the rear lights and the 3rd stop lamp, its likely water is ingressing through one of those, and yes it will take out the closing tailgate module. Might be worth buying the wiring plug and connectors and repining that first to see if its just a rotten connection, but I highly suspect the unit has failed.

Once you have repined it you could ask a specialist to check the actual values of the closing module.

Thanks for reply Steve. I replaced the seals around the rear tail lamps earlier in the year, had puddles of water either side in the cavities above the wheels. Took a fair bit of dabbing with kitchen roll to remove it, especially on the passenger side. After sealing around the rear windows the leaks stopped, dry as a bone now either side. I suspect if a new leak is present then the culprit is likely the the 3rd stop lamp as you suggest.

I've checked the cabling as far as possible and it looks in good condition. I think the best bet as you suggest is to get it booked in for a check over. Took the dog to the vets tonight and as soon as I set off the tailgate warning light came on even though the boot was closed.

When the motor whirrs it will lift or close. When it fails to lift or close no noise is heard from the motor.

Cheers

Lee

 

[CrustyClam]

Had some spare time today so as a last throw of the dice I thought I'd have another faff about.

Filled the reservoir on the pump to just slightly above the + mark.

Opened the Tailgate control module to see if any dry joints on solder connections or water damage. Looked ok, bit of damp creep on pcb, cleaned that up.

Removed all the tailgate trim to have a look what's underneath ( took me a while as was worried about breaking trim). Bottom moulding was the worst, had to use some force and it really sprung off, that much so it launched tailgate opening/closing switch cover over the neighbours fence. Had to knock on and ask for it back.

I didn't remove the 3rd stop light, i saw no signs of water ingress. Fingers crossed the water ingress was from past leaks.

Now the strange bit was that after removing all the internal trims the tailgate opened and closed perfectly. At first because the tailgate button was removed I thought maybe that was the issue, plugged that back in and still ok.

It only went pear shaped again when the tailgate opening/closing button got in the way(was dangling by wires only) and stopped the tailgate closing. After that it went tits up again.

When it opened and closed ok the lights turned on and off ok in the cabin area. Given the tailgate warning lamp has been showing I am suspecting a switch on that issue, just wondering if this can cause a wobbler in the overall action of opening and closing.

 

[CrustyClam]

Sorted, ended up being the manual tailgate handle which contains a micro switch. Was getting stuck in the open position.

Bit of cleaning and lubrication and lots of opening and closing has freed it up. Tailgate opening and closing ok now.

 

[ajlsl600]

grand job , i thinking of getting one of those ml and shifting my sl had any other worry some dramas ?

 

[EmilysDad]

Sorted, ended up being the manual tailgate handle which contains a micro switch. .....

That looks to be the same handle as on mine. And it was nearby (where I have a 'chrome' trim across the back) where the water was entering my tailgate ..... coincidentally my tailgate has been behaving itself since I sorted the water ingress.

 

[CrustyClam]

That looks to be the same handle as on mine. And it was nearby (where I have a 'chrome' trim across the back) where the water was entering my tailgate ..... coincidentally my tailgate has been behaving itself since I sorted the water ingress.

Interesting you say that as when I removed the handle a small amount of paint from the inside of the tailgate was stuck to the handle rubber seal. On inspection a tiny area had rusted so water must have managed to get in some how. (Treated with a rust preventer now) I used some gummi pfledge on the handle seal before refitting.

Will be monitoring over the next few months to see how things go. Any more signs of water ingress I'll remove the chrome trim to inspect. (Was on my list to replace at some point anyway as it has a couple of tiny bubbles on it)

Thanks for the heads up

 

[CrustyClam]

grand job , i thinking of getting one of those ml and shifting my sl had any other worry some dramas ?

A few issues but tbf some are just plain wear and tear that may be expected for a car over 10 years old

Airmatic shock replaced - leaking
Breakdown due to pulley tensioner giving way and belt shredding. (Around 60k)
Oil leak around sump - good few hours labour on that one.
The nasty one I could have done without was 4 x cam adjusters and 4 solonoids. (Cam adjusters being a well known issue)

Oh and last MOT a minor oil leak noted. (I have actually noted some drips now on the drive area)

I have my car booked in tomorrow which was going to be an investigation for the tailgate, but am going ask if they can check the leak out instead since its fixed. I can see which side the leak is on due to drips, it looks like it maybe from top part of engine. Given the rocker covers have been removed recently and I didn't have any signs of leaking before I'm hoping its this.

 

[EmilysDad]

.....
Will be monitoring over the next few months to see how things go. Any more signs of water ingress I'll remove the chrome trim to inspect. (Was on my list to replace at some point anyway as it has a couple of tiny bubbles on it)

Thanks for the heads up

I think mine is different from yours but similar (this mine .... https://www.ebay.co.uk/itm/MERCEDES...m=283171307660&_trksid=p2045573.c101006.m3226)
The two screws screw into 2 ally threaded inserts that had both corroded & become lose ... hence the water ingress.Mine is now just bolted in place (stainless of course )

 

[Andy R P]

I would check the seals around the rear lights and the 3rd stop lamp, its likely water is ingressing through one of those, and yes it will take out the closing tailgate module. Might be worth buying the wiring plug and connectors and repining that first to see if its just a rotten connection, but I highly suspect the unit has failed.

Once you have repined it you could ask a specialist to check the actual values of the closing module.

Do you know where I can find the tailgate control unit on my W166 ML350?