Brodie320

So i have recently purchased an alarm (cheap 1 way one) off a local trading site and have been reading up on installing it for a few hours now. People seem to be running into trouble with working around the vacuum central locking unit? My car did not come with a OEM alarm, nor did it come with the chipped key..Can anybody provide any more information on this? And how many people have successfully installed their own alarms into these cars.

Would i be able to work the central locking system by wiring into the door lock/unlock switch on my dashboard, as shown below?

Chief Wiggum

Your car is equipped with a vacuum door lock system, so the alarm will need to be programmed for an extended door lock pulse, plus you're going to need a couple relays.

Door Lock Diagram:
http://www.the12volt.com/relays/relaydiagram5.html

Brodie320

so just hooking the door unlock and door lock signal into the back of the unlock/ door function as pictured in the above post would not bypass having to run two relays?...i did read of somebody who had done this...but they did not mention weather or not they had been running two relays.

Chief Wiggum

No, it's not going to work. It's a multiplexed circuit at the switch, that why the door lock interface needs to done at either kick panel or at the pump.

Chief Wiggum

Wiring Diagram

Brodie320

Turns out you are correct cheif...has anybody seen any diy alarm installs for the w210? i have hooked up everything except the central locking, which is what i initially bought it for..I am not the best with electronics, relays and what not. I dont even have any idea where to get those relays in new zealand.

There was one guy on a forum who posted from australia saying he hooked into the door lock switch on the dash, but did not say how or what he done to get it working, and i am not a member of their forum

Chief Wiggum

I already posted a vehicle wiring and relay diagram. You can buy relays and connectors from Amazon, eBay, or any car audio shop.