W124 central locking with option 880

[acm718]

Hi, my first technical post!
Am now the proud owner of a '94 E320 estate. Which doesn't lock. Yet.

I have found that the vacuum pump just 'clicks' once, when the remote infra red key (now definitely coded to the car thanks to a search on here!) is pointed and pressed at the drivers door sensor.
Option 880 is remote locking, via the driver door and bootlid. Passenger door still has the keyhole to manually lock/unlock that door.
The car also has an immobiliser/alarm, seemingly factory-fitted - sensor on drivers side A pillar, siren front inner wing on factory bracket, and led on the switch panel on the centre dash area.
What I have is http://www.ps2cho.net/downloads/MB CD/W124/w124CD2/Program/Chassis/80-400.pdf#page=9 I think.

I also get a 'click' on relay A behind the fusebox under the bonnet.
But no locking, no vacuum pump movement or noise.

So, to my questions...

Am I right in assuming the vacuum pump is cabbaged, as I just get a click from it, and also (this is the complex bit, at least to me!) am I right in assuming the 880 option is combined with the factory-fit alarm/immobiliser - so that without the vacuum pump operating, the immobiliser also gets confused?

I can 'lock' or 'unlock' using the remote sensor, to get the relays to click and the red and green lights to come on on the door sensor, but the immobiliser (and the warning led on the dash) only seems to respond to the passenger door lock being locked/unlocked.

Currently, I'm thinking the immobiliser circuit is only operated from the passenger door lock operating (as it would if the vacuum pump worked) and sending a lcoked/unlocked signal to the immobiliser, rather direct than from the remote key - does that sound daft?

Thanks in advance

 

[jaymanek]

you are right.. the passenger door may be the only one that is linked up to immobiliser with the key blade... does your drivers door have a blade lock? Shouldnt think so..

Anyway, i think the pump is under rear seat... sometimes they come back to life with a tap..

 

[acm718]

Wow, that was quick! :bannana:
Yep, passenger door is the only one with a keyhole - driver only has two pretty leds and a sensor on the handle.
I have attended to the vacuum pump already, using my largest percussion adjuster, but no sucky sucky. I think I need a new one.
But if you reckon the passenger door sends the signal to the immobiliser, then at least I'm going in the right direction, and a new pump should sort it.
The engineering on this thing really is amazing, has to be said. If they could use five screws instead of one and a tie wrap, they did

Thanks!

 

[Dec]

I was wondering if you had a similar link to the one in your first post for a W202 1994 Inferred Remote Control, as it is very useful info.

Dec

 

[acm718]

Hi, no I'm afraid. Just have a go googling - I had a go using 'w202 workshop manual download' and just found this on first google results page...

Manual book w202 eng - Rapidshare Search

BUT I accept no responsibility if your PC blows up after downloading it!

 

[Dec]

Thanks for that, I’ll give that a go.
Going back to your original problem, have you tried running the pump independently of the cars electric’s via the battery or a battery charger, this should rule in or out the pump as a fault.

Dec

 

[acm718]

That's a good idea - but I'm getting a click at the pump (looking inside it I think there's a relay in there behind the circuit board), so I'm guessing it's getting something.
The two pin main supply to it is good, and there's also a three pin circular plug, with voltage there too - I think this comes from the remote module mounted next to the pump.
Think this evening's entertainment is to fiddle with the key fob and the multimeter together to see if the voltages on the 3 pin plug switch on/off.

 

[pupsi]

Off topic question here, but how did you code your infra red key?
Can you please direct me to a link, tried searching but found diddly!

 

[acm718]

Hi, in my pre-purchase internet adventures I found this which seems more than handy if you're W124-minded
Scroll down to 80 - central locking - and then choose 80-420 to synchronise.
I did both the ignition on and the key in passenger door lock methods - not sure which worked!

Next episode - The Sunroof!

 

[acm718]

Just to report.. after a bit of a struggle to get a cheap vacuum pump specific to cars with the infra red locking and factory alarm, Rob at Three Pointed Parts came up trumps with a pump for £30 and some other bits and pieces as well.
Credit where credit's due - highly recommended
The infra red locking means as far as I can tell, an extra single brown wire on its own plug and socket, so most pumps won't work.
Pump now here, plugged in, and... perfect, apart from an air leak traced to the fuel filler flap lock meaning pump pumped for a good ten seconds each lock and unlock cycle, presumably until a timer stopped it.
Air leak eliminated (flap lock disconnected and capped until I find a new non-leaky one) and all is good. Pump on for a couple of seconds every time, even the alarm works.
I'm guessing being this lucky so far means something huge is about to bite me in the proverbial...