C200 W202 - won't start & central locking broken

[AndyRobin]

Do you get the click from the pump when you use the remote fob lock button or unlock button or boot button?

I can hear a click each time I press the lock or unlock button on the remote. The boot button is a bit temperamental - it will click the first time and then will not until a few times later.


Do you get the click from the pump when you use the pull up boot switch beside the mirror adjuster switch?

Same as the remote button, it will click when I first get in and try but then won't for a bit, but will a later on if I wait for a while.

Cheers,
Andy

 

[Dec]

I would seem the remote fob, switches and fuses are working ok and either the pump motor is dead or there is a fault on the pumps PCB, below is how it comes apart, a different version to yours but same idea.

When the pump components are out of the casing its possible to plug all the electrical plugs back in again and operate the remote, this will help to identify what’s clicking and if the motor is making any noise or getting hot. No need to connect any Yellow / White tubes.

Dec

 

[AndyRobin]

Hi Dec,

I disconnected the vacuum pump and looked inside. There was a really strong smell of burning when I opened it. I then connected it back up without the airlines and tried to lock and unlock and there was just a click sound, I couldn't here anything else running like a motor?

One problem I have now though - after disconnecting one of the electrical cables to the pump the second time, the alarm went off and there was no way to turn it off!

In the end I took out one of the fuses in the boot for the alarm and it has stopped. However, if I put the fuse back in the alarm will continue.

Any ideas what has triggered it? I understand it will still be using up the battery even though the fuse has been removed? Is there anyway to turn it off?

Thanks,
Andy

 

[Dec]

If the Green circuit board in the vacuum pump is unburned/undamaged then the pump motor has burned out, the plastic coating on the motor windings (Wires) stink to hell when the melt.

A replacement pump from ebay might work, if not, then you could take the pump MOTOR from an ebay pump and fit it to replace the one that is burned out.

The alarm is probably triggering itself because it is faulty, it should disarm when the ignition is turned on, if it doesn’t disarm then its defective and needs to be unplugged/removed from the car.
Unlocking the car with the remote should also disarm the alarm but given the presence of a faulty vacuum pump that is not going to work.

That alarm is probably the original factory fitted unit, if so, then its now 16 years old, the siren becomes faulty and can cause all sorts of trouble when the get past 10 years of age. See post #2.
Below, inside my siren, removed about 2 years ago.

Dec

Edit, this might be a bargain, just for the pump motor on its own... http://www.ebay.co.uk/itm/MERCEDES-...rts_SM&fits=Plat_Gen:W202&hash=item4ad9caa84a

 

[AndyRobin]

Thanks Dec. I am going to order a new pump off eBay.

I wasn't able to get the alarm to stop even with the key in the ignition. I even started they car up and the alarm was still going.

I can't understand why it went off though? It was triggered when I disconnected one of the cables from the pump but I had done this before a few times with no problems.

Any ideas how long I can leave it with the fuse removed? I would like leave the alarm in place until I get the new pump just to see if that will shut it up. Do you think it will be ok for few days?

 

[Dec]

You could chance it, I’m not sure what the situation is when the fuse is removed, that is, I’m not sure if power is still going to the siren or not.

A proper working alarm, when triggered, should sound the siren for 30 seconds and flash the hazards for 3 minutes and then reset itself… even if a door is open. As I said before, turning on ignition should silence the alarm… that is, if it’s not faulty.

Dec

 

[AndyRobin]

I have ordered a new pump from eBay, just waiting for it to be delivered.

In the meantime I bought a syringe to use on the air lines.

Attached pic shows what each line controls.

Using the syringe I managed to open the boot via the 3 white air lines.

I am wondering whether the other 2 white lines control the rear head restraints?

By the way, I put the fuse for the alarm back in briefly today and the alarm still sounded straight away so somehow it has been permanently triggered.

Cheers,
Andy

 

[Dec]

The rear head restraints are usually white, it’s strange that the boot shares the air with them, don’t understand that at all.
Syringe was a good idea. With the boot lid in the fully open position, flood the keyhole with WD 40 and leave the lid open for a while to allow gravity to let the oil soak down into the lock, repeat this every few hours and try turning the key left/right.

When you put the alarm fuse back in and the alarm went off, turning the key in the ignition should disarmed the alarm, if it doesn’t then the siren is faulty.

Hope the replacement pump works out ok for you.

Dec

 

[kk2]

Hi Guys,

I have been reading with interest this posy as it seems to replicate my problem.

I have a Mercedes 1998 C class W202. My [COLOR=blue !important][FONT=inherit !important][COLOR=blue !important][FONT=inherit !important]ignition[/FONT][/FONT][/COLOR][/COLOR] does not work at all (does not grab the remote key nor turn), and the central locking completely dead.

Car was left a number of weeks without a battery connected. My boot/trunk did not open so I cut out the ski pass in the rear seat and just managed to connect the new battery.

However the lights, radio, clock do work, so new [COLOR=blue !important][FONT=inherit !important][COLOR=blue ! important][FONT=inherit ! important]battery[/FONT][/FONT][/COLOR][/COLOR] that is connected does work.

The remote keys both have been cleaned and the transponder checked and there is a signal. All fuses have been checked (that we know of, front and back [COLOR=blue !important][FONT=inherit !important][COLOR=blue !important][FONT=inherit !important]fuse [/FONT][COLOR=blue !important][FONT=inherit !important]boxes[/FONT][/COLOR][/FONT][/COLOR][/COLOR])

Reading Dec's solution he says that the vacuum pump should be disconnected but I have no way of getting to the boot/trunk (other than the small square I cut out to get the battery fitted), so would this be a problem in resolving the ignition and locking issue?

Many thanks

 

[Dec]

Connect a battery charger as illustrated below and use remote to open boot.

Dec

 

[kk2]

Thanks for the reply Dec,

That was the first thing I did once I managed to get the new battery connected. But nothing happened.

I have used that terminal in the past to get the boot open but this time although there was power registering from it there was no ignition or central locking functions.

From reading around and your replies my 'guess' would be to get to the alrm and check the alarm battery and/or disable it and see if the car would start.

Or is that a dead end approach?

 

[kk2]

Just something I noticed from your picture. Is the negative terminal/connection significant (what is that?). I basically put the negative on a part of the chasis. Is that from the battery charger?

The reason I changed my battery and then accidently locked the boot without a battery is that the car dies on me twice. Once while driving along at a slo speed and once when I parked up. Both times after 10 minutes wait it started again. Whether that was the main cause, the battery when checked was pretty much useless.

 

[Dec]

A faulty alarm won’t stop the car from starting.

The battery charger will still open the boot even if there is no battery in the boot.

The battery clips MUST be clean and making good contact.
The Negative - clip is on the large lifting eye on the engine, this is the best place, and it should not be painted and should be bare metal.
The Positive + clip is as illustrated in picture.

Are you sure your battery charger is good?
You should be able to turn the ignition on once the charger is hooked up, you should then be able to operate the centeral locking/boot open switch in the cabin.

Dec

 

[kk2]

Hi,

Now I am confused. It was my mechanic that did the checks and used a another battery to try and open it from the terminal you show in the picture.

If that should open it and get the central locking working then why is my car not starting (with a new battery attached).

It sort of made sense that if the alarm /immobiliser was not quite right then that would prevent the ignition and locking from engaging. I am confused.

 

[Dec]

Will the hazard lights work?
Will the outside parking lights work?
Will the courtesy lights work when a door is opened.
The above should work if there is a battery connected, correctly, inside the boot.

The central locking should work from cabin switches or the remote buttons.
If you have a factory fitted alarm then it shouldn’t have any effect on starting the car, the immobiliser is disabled by inserting the remote fob into the ignition and turning the ignition on.

Have you tried the key blade in the boot lock?

Dec

 

[Dec]

If you have a ski hole then you can remove the 2 bolts in picture below so you can get the boot lid open.

See posts 35 and 38 here… http://forums.mercedesclub.org.uk/showthread.php?t=73958&page=4

See also...http://forums.mercedesclub.org.uk/showthread.php?t=53189]Boot lock fix - Mercedes-Benz Owners' Forums

Dec

 

[kk2]

Hi,

Outside lights, radio work. So that should mean battery is ok? Charger looked ok.
First thing I tried was using the manual key to open the boot with loads of WD40 but appears that it is a broken lock.

I did try to get to those bolts but basically need a longer attachment to get on them.

Key fob has a signal (tested it using the camera technique), so why does the central locking or ignition not work.

Are there swithces or fuses that could have blown that are not in the obvious place.

Is it a re-progam job? Basically if it is something simple then great but if it means a good few quid to fix at a dealer then it is not viable.

 

[Dec]

You seem to have enough juice in the battery to release the steering lock and run the vacuum pump to unlock the car.

Check all fuses in any way related to central locking / vacuum pump, fuse box unde bonnet driver side, there are also some fuses passenger side, picture below… remove 4 screws on large cover to open.

Other fuses in boot relating to central locking.

Boot lock is likely seized up through lack of use… very common problem… keep at it with WD40.

The two bolts may be the quickest way into the boot.

Which key fob do you have?

Dec

 

[kk2]

Thanks for that Dec,

My fob is the the top left one. I did the mobile phone camera test with it.
My mechanic did check the fuses but I will try again.
In one of your pics you point at a purple wire. Is there anything I need to check with that?
I have tried a lot of WD40 in the boot lock but maybe I need to give it an actual hour working it.

The whole episode began with trying to connect a new battery in the boot. I thought once that had been done then the boot would open as well as the central locking.
My point being that even if I did get the boot open through taking off those bolts I am not sure it would make a difference as the central locking and ignition appear dead. Yet there is enough power to turn lights on etc.
If I go through these checks again and have no luck could it somehow be a resetting of codes with the immobiliser (I am guessing here).
As I said before if the cost of repair is more than the car then I will consider scarpping it but could be something minor then it would be a shame to get rid of it not knowing this.

 

[Dec]

First you have to get into the boot, it could take forever with the WD40… no guarantee that it will work, the only sure way in is by removing the two bolts.

Then you have to check if the car battery is connected correctly, there are 3 wires that connect to the Positive + battery terminal… 1 thick, 2 thin… maybe one is not connected properly.

Then there are the fuses in the boot, the have to be checked too.

Your car originally came with the flat emergency key in the picture, bottom left, are you sure that you are not in possession of this flat key, it might be with the cars documents/User Manual.

The Purple wire is not relevant to your problem, the picture in post #38 is just to show the location of other fuses.

Dec