Need help with 300SDL keyless entry install

[Chad300tdt]

I'm trying to install a keyless entry in my 1986 300SDL and I'm having trouble.

Here's the central locking pump:


Here's the factory wiring diagram:


Here's the wiring diagram for the keyless entry:


I know where to hook up the power, ground, and tail light confirmation wires. I'm not using any additional actuators and just want to hook this up to operate the locks via the pump in the trunk.

I'm getting confused about which wires to hook up for the lock/unlock feature.

On the keyless entry diagram there are 4 wires noted for this.

1 (Brown) = LOCK (-)
2 (White) = UNLOCK (-)
4 (Blue) = UNLOCK (motor)
6 (Green) = LOCK (motor)

I'm assuming I should only worry about using wires 1 and 2 since it looks to me like 4 and 6 are for operating additional actuators, but where should I splice them in?

Please help!!!!

[Chad300tdt]

My other thought is maybe I should splice wires 1 and 2 with the yellow wire at the pump. Then splice 4 and 6 with the green and blue wires at the pump.

[mplafleur]

Which kit is this?

[Chad300tdt]

The brand is Auto Guard. I bought it on ebay.

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=230398217838&viewitem=#ht_20881wt_1167

[boblo_home]

I think you bought the wrong control unit. You need one with Pneumatic capable, it does not say that in the eBay description.

Does it say the car has to be 1991 or later?

[LandYaghtLover]

Correct. I did lots of reading on this one. You need a unit that can be set to electric or pneumatic. When set to pneumatic it will hold the open/close circuit longer to give time for the pump to operate.

[Chad300tdt]

Take a look at the diagram I posted for the unit. It says it can be set for 0.7 seconds for power locks (electric) or 4 seconds for central locks (pneumatic).

I already pulled the jumper so it's set for 4 seconds which should work fine.

[boblo_home]

If it can work in Pneumatic config then the wiring diagram you posted is wrong. You need the diagram for pneumatic configuration, setting the jumper is not enough.

If you have the correct wiring instructions then you need to cut the yellow wire. That is the ONLY wire you need to cut, plus +12V and 0.

[mplafleur]

Originally Posted by LandYaghtLover

Correct. I did lots of reading on this one. You need a unit that can be set to electric or pneumatic. When set to pneumatic it will hold the open/close circuit longer to give time for the pump to operate.

Last year I designed my own keyless entry system using an OEM module from Ford. I had to design a board that would take the output pulse of the module and hold the line for 3-4 seconds for the Mercedes pneumatic system to work.

There is one signal wire going to each door lock and it can either be at 12V or ground. Grounded is locked I believe. If you want to unlock, then short that wire to 12V for a couple of seconds and remove it when the doors unlock. When the doors are unlocked, the wire will now be 12V.

[auspumpen]

This can be accomplished quite easily for about $30, with just four wires and no relays. Link

[Sev]

http://www.mbkeylessentry.com/1.html

got 'em installed on three of our Mercs

[Zacharias]

What if I have a pre-84 model?