How to Change the Code on Simplex Cipher Door Lock

Disengage the passage feature of the lock. (Not all models have this feature.) The turn key or the knob must be in a vertical position.

Insert the control key into the combination change plug assembly. The control key comes with the lock.

Turn the key counterclockwise for unscrewing the cylinder.

Remove the plug of the combination change. This gives you access to the combination change sleeve.

Turn the knob, on the outside, clockwise. Do it once, but do it all the way.

Release the knob, but ensure the latch does not retract.

Enter the code’s existing combination. If you install a new lock, use the default combination, which is the same for all Simplex Cipher door lock models. Depress "2" and "4" at the same time and release. Then depress "3" and release. You will hear a slight click while you depress each button.

Engage the change sleeve of the combination. To do this, insert the spanner wrench. Turn the wrench gently clockwise to bring it the stop position. You will feel a slight click. Turn the wrench counterclockwise and bring it to the stop position. Remove the wrench and turn the knob on the outside clockwise. Turn it only once until it stops. Release, and do not let the latch retract.

Enter the new combination by depressing the buttons carefully. As you depress each button, you will feel a slight click. Each button can be used only once, but you have the option of using one button or all five, whichever suits you better.

Turn the knob on the outside once. Turn it all the way in the clockwise direction until it stops. Hold it in the position and allow the latch to retract. Once it retracts, you can release the knob.

Turn the knob and bring it to the stop position (turning clockwise). You will see that the latch does not retract this time.

Re-secure the change plug assembly of the combination by screwing it in a clockwise direction using a key. Remove the key when you are done.