Rear Tailgate A180 2006 2.0 CDI

[Tezz]

working my way through niggles on car.

Tailgate sometimes unlocks but most of time will not, but I can unlock using the red catch from inside of trunk.

Before I just buy a new lock, thought I get a bit of help.

Looking at trim on inside of door is loose in a few places like the clips are missing or broken, kind of suggest to me someone's been looking under there.

So unlock car cannot open tail gate, using key or button, but hear comes the odd bit, was out other day went over a speed hump, door light came up on dash, got out and tail gate was open. yesterday after new battery fitted tried the tailgate again, nope would not open, took car in car wash ( roller type) came out and again door open light came up on dash, got out and tailgate was open, so not sure what's going on.

I would have thought if lock damaged ect once locked that would be it, which seams to be the case if I lock it and don't try to open again from rear handle.

But could it be something is putting pressure on lock, tail gate out of alignment, lock or catch ? that the electrical side of things partly unlocks tail gate, and then when you go over a speed bump or put pressure on door it releases presser and tail gate pops open? Just find it odd both times its popped open were after I tried unlocking and then went over a bump or in car wash.

All input greatly welcome.

Tezz

 

[Tezz]

plugged my icarsoft in for first time, checked past faults were quite a few for battery voltage ( battery replaced 2 days ago ) right at end was fault for rear door it said, hung up or short circuit

 

[BlackC55]

It will probably be a faulty lock. Very common issue.

 

[Tezz]

Thank you.

will look for working 2nd hand unit on ebay before splashing out on a new one, just to make sure is lock its self

Dose anyone have part number or other cars that use same lock like W245 B class, have found on ebay when you search for just one car get a limited selection

Many Thanks

Tezz

 

[GLK]

One other possibility, other than a defective lock:

The tailgate release button on pre-facelift W169 is rather bad - the rubber coating is almost always damaged along the edges, hence water ingress - resulting in the problems you've described:

I have replaced the handle with a new one from the facelift model - this got a new type plastic button, and a nicer overall look.
You'd need an adapter for the existing loom / connectors - about £8 from Mercedes.

(ignore the red/black wired connector on the right - my mod - the rest is original OE harness)

New button:

Handle fitted:

PS The W245 handle is different, but the lock is the same.

 

[Tezz]

many thanks that was exactly what came up on my icarsoft

what handle should I search for on ebay and what was the MB part number for the adaptor

Many Thanks


Tezz

 

[GLK]

The wiring adapter - A169 540 3135
The handle - A169 740 1993
You'll need 4x new dowels - A 000 998 4685

I also bought a new set of screws, but the old ones will be fine as well.

 

[Tezz]

Many thanks

as new lock is on order I will fit that first and see if that cures the issue, but upgrade you listed seams to be a good mod ether way

Many Thanks


Tezz

 

[Tezz]

so swapped out door lock, made no difference so guess onto handle mod next

 

[Tezz]

can you test the switch ? there's 3 wires going to the switch, if I locked the tail gate lock manually with tail gate open, disconnected handle and jumped say 2 of the wires to by pass switch,would lock open? if so what of the 3 wires would need to be jumped

Thanks

 

[GLK]

Now you making me work hard, and I'm genetically very lazy ...


S15/1 is your friend

 

[Tezz]

Many Thanks

 

[Tezz]

so was having lunch knock on door your car alarms going off, went to switch it off car dead, doors not open nothing, luckily with last battery issues I had lube up lock to use emergency key to open, would not shut off, no ignition fek all, called out RAC again, was coved as they just fitted new battery, this was obviously a different issue.

Battery was reading just 4 volts, charged it for a bit and jumped it, car fine, he checked system said was quite a big battery drain, lol so I owned up to changing a faulty door lock, he was cool, disconnected lock and handle ect open and closed boot man and drain went away, reconnected just lock no drain, reconnected handle tried that big drain came back and stayed there, so there we have it.

Anyway too handle off to have a look, 1 there was loads of dirt left in there from water ingress, foam seal was green and hard.

Took handle apart to find switch, removed the tiny on/off switch from handle, tried pushing it to make lock work nothing, striped back of sheathing on each wire, just past switch, I fully locked latch with tailgate open, jumped them, lock worked perfect

looked at inner working of switch housing, so complicated when a simple momentary on off switch would have done, but it was the micro switch itself that had failed internally, probably cost about 50pence.

so looks like def need new tailgate switch, as handle is basically scrap and you can buy about 10 momentary micro switch's for £3, drill small hole and bypass handle switch, I might have a play as I have soooooooo much time on my hands.

will eventually replace handle, but would be cool to know if that small switch is real issue

Still cant believe how quick the hung lock drained my new battery

 

[Tezz]

I did disconnect both the rear lock and handle yesterday, went out to car today and started straight away no issues

so the offending article from the handle looks like this

https://uk.rs-online.com/web/p/microswitches/9076797/

got the maker I think? is Marquardt, the one shown is an on on and has 3 wires, one in my handle is of on 2 wires, but apart from that they look identical, I have taken a pic of my part and emailed the company to see f they can shed any light, the 3 wire ones are on eBay for about £10

To test my theory I have order a waterproof micro momentary switch £2 its only 8mm so should fit in plastic of handle , will splice and solder in and see what happens when I push it and how long it last.

Yes will get a new handle, but im curious, want to know 100%

Plugged my icarsoft in and had a look at sam codes, were a few for low voltage and one for hung rear door switch, have cleared them all in the disconnected state to see if they come back when I next use car and if they return after my bodge lol.

Command unit has had a nut do after RAC jumped car, but that's for another day, I would assume needs a soft reset but who knows with this car. from all the posts I have read this seams a common issue, do I have radio code NOPE lol, will probably just pull unit.

I have come to the conclusion the electrics on car are ok when new, MB ability to keep water away from them is severely lacking :-(

icarsoft basic but works well, mind you anymore complicated and think I would be in trouble, remember for my old car had workshop software on PC, but before I did anything made a back up fle, was messing about, killed car, door locks windows could not get out ect LOL, just reinstalled back up all fixed.

 

[Tezz]

PS if you are local to IG10 3 and need to read or clear you codes all welcome to use icarsoft if you know how to use it that is lol, def don't ask me

 

[Tezz]

still waiting on micro switch to arrive, so I can see if my £2 fix works. intention is just to replace the micro switch with a momentary off/on one, there only 2 wires to existing in handle and if I connect together the lock works perfect, im assuming the switch is just that a simple on off switch that send signal to lock and its the lock that feeds signal back to sam

On plus side, no more battery drain since I disconnected the rear lock and handle, left car for a week went out started no problem, so at least I got to bottom of battery issue

Command unit now seams to have settled down everything that was working is working again with exception of GPS

 

[Tezz]

got to mess around with handle after switch's arrived

after disconnecting lock and handle, battery drain went away, No new codes on icarsoft for rear door.

pulled out and disconnected the small micro switch and tested, def knackered.

drilled hole in rear handle and fitted new switch, same type you find on a jet wash

Put all back together and tested, rear door now locks and unlocks perfect, no new codes on sam after fitting, im please cost me £3, been on for a few days will have to see if any long term effects on battery or system, you cant see switch as almost flush from outside when lid closed. all trunk lights ect are
working

THIS IS NOT a fix im suggesting anyone try , I did it as was just curious if it was a simple failed of a part that probably cost 50p was issue and killing my battery, seen a few new handles for sale about £120, or carry out other mod posted above By black55

There are hundreds of micro switches out there im sure given more time I could have rigged up an internal one to replace MB part and will keep eye out on ebay for handle as iv basically just drilled a hole in this one

other point I found, was raining when I changed handle over, when I removed it was full of water like the foam seal had failed

Hears a pic sorry for quality.