JDM central locking

[b3lha]

The central locking unit is located above the glovebox, next to the cruise control unit. It's the unit nearest the door, with the plug visible when you look upwards from the footwell. The speed sensor wire is yellow with a red stripe - just cut it to disable the feature. I know because I did it by accident when modifying my cruise control.

Personally I quite like the was the auto-locking works. You don't have to pull the driver's handle all the way back to unlock the doors. Pull it until the doors unlock, but not so far that the driver's door opens.

[svxistentialist]

Originally Posted by b3lha

The central locking unit is located above the glovebox, next to the cruise control unit. It's the unit nearest the door, with the plug visible when you look upwards from the footwell. The speed sensor wire is yellow with a red stripe - just cut it to disable the feature. I know because I did it by accident when modifying my cruise control.

Personally I quite like the was the auto-locking works. You don't have to pull the driver's handle all the way back to unlock the doors. Pull it until the doors unlock, but not so far that the driver's door opens.

Thanks for that Phil.

What you say agrees spot on with what I had deduced in an earlier post, with the addition that the signal code from the Speed Sensor 2 also inputs to the control box via the Yellow and Red wire.

What I am now going to do is put a US market driver's door actuator on my passenger door. I will feed the three lhs wires into their own loom, and the fourth Yellow/Red one I will splice into the same colour going to the control, which is a short run from there.

That way, the doors will lock for safety as presently, but the passenger inside latch will disarm the central locking, allowing them to leave without all the huffing and turning.

Joe

[b3lha]

Joe, you will have to think carefully about how you splice it in. I worked late into the night trying to figure out the central locking on our Legacy and I assume the SVX uses the same system.

There is a single control wire running between the lock in the driver's door and the control unit. The wire is in one of two states. Either "grounded" (doors unlocked) or "not grounded" (doors locked).

When you slide the lock button up, the mechanism moves and closes a microswitch which grounds the control wire. Then the control unit sends an unlock signal to both actuators. When you slide the button down, the mechanism moves and opens the microswitch, removing the ground from the control wire. Then the control unit sends a lock signal to both actuators. Follow me so far?

Now if you are modifying the system, for example to fit an alarm, you are faced with the problem of how to activate the central locking without impairing it's normal function. This is not so hard when you figure it out:

To unlock the doors, you momentarily ground the control wire. Then the control unit sends a lock signal to both actuators, the mechanism moves, the microswitch closes and maintains the ground on the wire - keeping the doors unlocked. To lock the doors, you momentarily break the connection between the driver's door lock and the control unit. Then the control unit will send a lock signal, the mechanism will move, the microswitch will open (removing the ground) and the doors will remain locked.

The word "momentarily" is very important in the above paragraph, otherwise the central locking will stop working in the traditional manner. I had to install a 12v relay to make it work with my alarm.

So in your scenario: The passenger pulls their handle which moves their lock to the unlocked position and closes the microswitch. This will then ground the control wire which will cause the control unit to send an unlock signal to both doors. Both doors unlock. Great.

But then you have two microswitches applying a ground to the control wire. How do you get the control unit to lock the doors? You must break BOTH of those ground connections. Pressing down one lock button will not do the trick because the other will be keeping the ground applied. You would have to press both buttons down in order to get the control unit to send a lock signal - which would be irrelevant because you've already locked the doors manually. Do you see what I mean?

I reckon it can be done with a relay or two, but I can't get my head around it this late in the afternoon.

Phil.

[svxistentialist]

Yeh.

I geddit. So the factory solution of a button on the dash was for a reason. It would not have been a two-position tumbler switch. It would have been a Push Once Momentary Interruption type switch. This would leave the driver's door operating as it should, opening and closing the earthed section as when lifted by hand to open, and getting the speed signal to close.

Right. I'm still thinking here.

Thanks Phil

[Dave at least has a simple solution in cutting the yellow red wire. he is not bothered if it locks or not on the move.]

Joe, Phil,

Yes, I have my solution for my problem, for which many thanks. But, reading other threads it would appear that taking the glove box apart to gain access to the wire to cut it is a nightmare. I shall give it a try and see how many screws I have left over at the end.

Thanks, Dave.

Phil,

Just a note of thanks. I have taken out the glovebox and found and cut the yellow wire with the red stripe. It has certainly stopped the speed-sensitive locking. Now I have to put the glove box back!

Dave

[svxistentialist]

Originally Posted by Blackbir2001

Phil,

Just a note of thanks. I have taken out the glovebox and found and cut the yellow wire with the red stripe. It has certainly stopped the speed-sensitive locking. Now I have to put the glove box back!

Dave

Good work so far Dave.

How many screws have you left over, then??

Joe,

All of them at the moment as I have to fix a problem with the aircon (see my other post) before I tackle the glove box again! It reminded me of a task I undertook with my dad many years ago - stripping a Hoover Keymatic washing machine to replace the main bearing. The shaft was held in place by every conceivable fastening known to mankind. The SVX glovebox is the same - why so many and so many different types of fastenings?

Dave