Retro fitting of remote locking - advice needed please

[tobyd]

Hi,
I'm thinking of fitting remote locking to my E280 estate and was wondering if anyone had done this. I've seen some kits on ebay such as Zentralverriegelung+Klappschlüssel Mercedes W123 W124 on eBay, also Fernbedienungen, Autoelektrik, Auto-Ersatz- -Reparaturteile, Auto Motorrad Teile (end time 12-Sep-08 21:00:42 BST) but have had no experience doing a job like this.
My car once had a mercedes approved alarm (scorpion) that were fitted at merc dealers back in the UK during the early eighties but it has never worked since I got the car and someone I had look at me told me it was dead.
Thanks for your time
toby

 

[bigasotonuk]

Hi,
I would think your car at that age would of had remote locking from the factory as the lower range c class of the same age did.
Remote locking was i believe not a feature of the alarm, but of the car, the alarm only interfaced with the remote locking.
Have you red & green LED's in the rear view mirror?
If you are not sure ask merc for a price on a key, if it had remote locking from build the key will be in excess of a £100, if it had normal key it will be about £15

 

[tobyd]

My car was just too old for the factory remote locking so i was looking to fit remote locking for convenience.

 

[nmacc]

This should be a relatively simple job. The kits you linked to on ebay.de seem to be good value, particularly if they include a set of 4 actuators; I'm afraid my German isn't good enough to be certain.

There are two ways you can do this IIRC (and I may not!); which way you choose depends on how comfortable you are working with auto electrics. The vacuum lock actuators on your 280T are driven by an electric pump which is switched by contacts in both of the front doors and the tailgate. There are three wires to each door switch: Brown, Red/White and a third wire whose colour depends on the door; I think it's Green for the driver's door, Yellow for the passenger's and Blue for the tailgate. In all cases Brown is chassis ground and Red/White is +12V.

When the door is locked, the switch in the lock connects the green (or yellow, or blue) wire to ground (or 12V, I can't remember which, but it's easy to check) and vice-versa when the door is unlocked. This triggers the pump to either lock or unlock the doors, as the case may be.

This is a long-winded way of saying that you can simply track down the cable coming from the driver's door and fit a relay to the remote control receiver so that it connects the signal wire to either ground or 12V, triggering the lock. If you're not comfortable with phrases such as "SPDT 300 ohm relay", then I suggest method 2:

Fit a single lock actuator in the driver's door. They usually come with a set of rods and clamps to enable you to attach them to the existing rod that comes from the internal lock button. They also usually come with a simple wiring loom that you simply plug together. When you press the button the receiver will simply move the button up or down as required; the regular central locking will look after opening the other doors.