How-to: Locked Out Prevention Circuit

[ZapWizard]

Locked Out Prevention Circuit

For a 2003 Mazda Protégé
By ZapWizard
www.ZapWizard.com

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You all know the feeling; looking in through your car window staring at your keys you just locked inside.

Most likely you left the keys in the ignition, opened your door, pressed the Lock button on the door, and walked away.

There is a easy way to prevent this, and it only takes two cheap components and some time.

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First the schematic. I designed this using the service manual, while my keys were in fact locked inside my car, and I was awaiting my wife to come home with here keys to unlock it.

As above: IF any car doors are open AND your keys are still in the ignition THEN your door lock buttons will not work until the keys are removed.

Any other condition and the locks work the same.

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You need only a few cheap parts.

• +12volt Relay capable of NORMALLY CLOSED (N.C.) contacts.

• Silicon diode capable of handling +12volts (I used a 1N4001)

• Four wire taps

• Wire

• Zip-Ties

• Double Sticky Tape

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First solder the diode to one of the coil connections on the relay.

The diode is marked with a white line, this should be towards the relay.

Leave about 6 inches of wire, and put heat-shrink tubing over the connection.

I realized later in this mod that it would be hard to follow without proper color-coding, so the above wire is later RED.

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Solder another wire to the other coil terminal. Again leaving about 6 inches of wire.

This wire will later be colored GREEN

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Take note of the relays schematic. We need to solder a wire to the switched terminal, and it's Normally Closed contact.

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Either cut or bend the other contacts that we won't be using.

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Solder a wire to each of the contacts that we left un-bent. Color coding does not matter here as it doesn't matter which connection goes where at the other end. Leave about 4 or 5 feet of wire.

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Here you can see my RED and GREEN wire change.

The circuit is now ready to take out to the car.

I also included some zip-ties and a piece of double stick tape.

[ZapWizard]

We need to locate all the proper wires that we will be tapping and cutting into.

First up is the Door Lock Control Box.

This is located just above your foot rest on the driver's side.

Some of following steps optional, but were required to first find and test the wires.

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It is pretty easy to find as it is bright yellow.

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Remove the connector, then test your locks. No buttons should work at all.

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Using the service manual we find that we need wire 'F'.

This is the GREEN W/ RED STRIPE wire.

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Remove this wire from the connector.

(This entire mod on the car-end was done with that tool, a Leatherman Squirt from Radioshack)

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Plug the connector back into the control box. Test your door lock button, it should not work.

This wire controls the "Lock all Doors", and "Unlock all Doors" signal.

The green without stripe unlocks and locks the driver's door only.

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Next up we need to get behind the Instrument Cluster. It doesn't need to be removed.

Follow my instructions from my LED gauge mod here:

http://www.zapwizard.com/car/guageleds

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Looking at the connectors on the back of the instrument cluster locate the far left connector.
Plugged into this connector is a WHITE W/ GREY DOTS wire. This is the Key Reminder Switch Wire.
My wire was already detached after doing the "Disable Door Chime" mod.
(NOTE: The door chime mod on my website is old, and also disables the courtesy light, disconnecting the above wire is the proper way to disable the door chime.)

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First I need to test this wire.
Indeed is has +12volts when there is a key in the ignition.
When the keys are removed this wire has no power.

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Next locate the connector at the far right.

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Remove this connector and look at it with the tab facing up.
The Door Ajar Switches are connected to the BLACK W/ BLUE STRIPE wire.
This wire is the middle wire near the tab.

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Remove this wire, and plug the connector back into the Instrument Cluster.

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Confirm that your Door Ajar Light no longer works.
Don't worry we will be putting this wire back, I only removed it to confirm I had the right wire.

[ZapWizard]

Now we are ready to install our relay circuit.
Using double sticky tape I attached the relay to the back of the instrument cluster.

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I then connected the RED wire (This is the one with the diode) to the White w/ Silver.
And then connect the GREEN wire to the Black w/ Blue wire.
Try opening a door with the keys in the ignition, the relay should trip.
If not try reversing the RED and GREEN connections, and try again. (If that works you installed your diode backwards)

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Trim your GREEN wire to size, and using a tap attach the GREEN wire to the BLACK W/ BLUE STRIPE wire.
Make sure and re-install the Black w/blue wire back into the instrument cluster.

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Since I am leaving my Key Reminder Switch wire detached from the Instrument Cluster due to the door chime, I didn't need to use a tap.
Instead I simply stuck the wire into the connector and secured it with tape and zip-ties.
If you still want your door-chime, reconnect this wire to the instrument cluster and use a tap to attach to it.

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The relay connection is now complete.
Push the black wires behind the instrument cluster and down to the Door Lock Control Box.

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About ten seconds later I realized I had to move the relay due to the metal bracket.

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Next we need to go back down to the Door Lock Control Box, and our GREEN W/ RED STRIPE wire we left disconnected.

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Cut the Green w/ Red wire leaving enough wire on each end to attach our wire taps.
Also trim the black wire from the relay to size.

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Next attach one black wire to each end of the Green w/ Red wire.

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Re-install the Green w/ Red wire into the Door Lock Control Box.

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That's it!
Now if any car door is opened, and your keys are still in the ignition then, your door-lock buttons will not work.

Be aware if you do leave your keys in the ignition, exit the car, press the lock button, and walk away, your doors won't be locked!
But since the car makes a sound when you actualy press the lock button you should be able to tell something is wrong when you press the button.

[Moeed]

Nice, I wish this existed before i got my compustar.

Very nice write up Zap, keep up the great work.

[NRRfrogmanP5]

yeah sounds good...why not press the lock button on ur keys and then ur sure they are in your hand

[ZapWizard]

yeah sounds good...why not press the lock button on ur keys and then ur sure they are in your hand

Something I have not got into the habit of for some reason, it's automatic, I press Unlock, open the car door, press the lock, then get out, all in one motion.

[Poseur]

moved to how-to

Great writeup as always man. Thanks..

[cyomega]

My solution to this problem? The valet key is in my wallet, tucked into one of the credit card pockets. I have never had an instance where I have left both my keys and my wallet inside the car. (although now that I've said this, I probably will...)

[loccusst]

Nice write up. If I didn't have a alarm remote that I always use I would definately use this. Only suggestion I have is to tell those who have no idea about relays where the wires are going to on it. Not everyone knows which is normally open or closed or if they need to use 87 or 87a......just a thought for those not electronicly inclined.

[Gbourdon]

Nice write up. Great work.