Hi @all,

I want to build a "tool" to manually enter or simulate the EKA procedure activation of the microswitches in the drivers side door lock. Like a switchboard with three? sitches for cdl, left and right. I have seen two versions online, one with three wires and one with four. As nearly everything on the p38 is switched by grounding, I guess I need four wires for three switches?
I plan to build a "switchboard" and use a door outstation connector from a spare wirking loom.
Can anyone help me with a diagramm of the circuit?
It´s for the early versions of the becm where You can´t enter the eka by the obd-connector.
Thanks in advance!

You don't need 3 switches, only 2. In fact, you don't need 2 switches, just 1 switch and 1 pushbutton. The keyswitch simply grounds one wire (the Blue/Red) whenever the key is turned in the lock, irrespective of which way it is turned. The CDL switch (on the Green/Red wire) is grounded when the door is unlocked and open when the door is locked. This is the reason the other doors will lock if the driver's door latch is unplugged, the ground is removed from the CDL switch wire.

You can either connect at the door outstation or at the door latch connector.

So you need to connect to the Green/Red wire, the Blue/Red wire and the Black wire (the ground). Connect your switch between the Green/Red wire and ground and your pushbutton between the Blue/Red wire and ground. The BeCM detects which way the key has been turned by looking at whether the CDL switch wire has a ground on it or not.

So to enter the EKA, you need your switch to be open, signifying locked, and press the pushbutton 4 times to simulate the 4 turns to lock. Then to enter your first digit, you move the switch to the unlocked position (switch closed so the wire is grounded) and press the pushbutton the correct number of times. For the second digit, which would be turns to lock, you move your switch to the locked position (switch open) and press the pushbutton the correct number of times and so on.

When entering the EKA the door must be closed, which is detected on the Purple/White wire (the door ajar switch), but I am fairly sure a ground is only on that when the door is open so that can be left alone.

Thanks a lot Richard!

This could be a sticky perhaps. Good explanation (as usual) Richard.

Gilbertd wrote:

You don't need 3 switches, only 2. In fact, you don't need 2 switches, just 1 switch and 1 pushbutton. The keyswitch simply grounds one wire (the Blue/Red) whenever the key is turned in the lock, irrespective of which way it is turned. The CDL switch (on the Green/Red wire) is grounded when the door is unlocked and open when the door is locked. This is the reason the other doors will lock if the driver's door latch is unplugged, the ground is removed from the CDL switch wire.

You can either connect at the door outstation or at the door latch connector.

So you need to connect to the Green/Red wire, the Blue/Red wire and the Black wire (the ground). Connect your switch between the Green/Red wire and ground and your pushbutton between the Blue/Red wire and ground. The BeCM detects which way the key has been turned by looking at whether the CDL switch wire has a ground on it or not.

So to enter the EKA, you need your switch to be open, signifying locked, and press the pushbutton 4 times to simulate the 4 turns to lock. Then to enter your first digit, you move the switch to the unlocked position (switch closed so the wire is grounded) and press the pushbutton the correct number of times. For the second digit, which would be turns to lock, you move your switch to the locked position (switch open) and press the pushbutton the correct number of times and so on.

When entering the EKA the door must be closed, which is detected on the Purple/White wire (the door ajar switch), but I am fairly sure a ground is only on that when the door is open so that can be left alone.

Yes if this work-around is done at the latch & the Purple/White is open circuit, the BECM will assume the door is closed !! So you can work on it with the door open :-)