Chip-Tools

ITDEENBGES

Finding the B+, IG SW and KEY SW fuses for the ZN067 using immobiliser Live Data

A practical method for pinning down the three points the ZN067 has to be connected to during the All Keys Lost procedure on H-type mechanical keys, when you do not have the factory wiring diagram to hand. It uses the immobiliser module live data while pulling fuses one at a time.

Procedure

1. Use factory wiring diagrams when you have them: they are still the safest route. The method that follows is for when they are not available on the car.
2. You need to find three things: 1) battery (B+), 2) ignition switch (IG SW), 3) key switch (KEY SW). The KEY SW is not actually found among the fuses: you unplug the connector going into the ignition switch and connect the dedicated ZN067 wire to it. Some trim usually has to come off, but in AKL situations there is no alternative.
3. Open the diagnostics menu, enter the immobiliser module and press "LIVE DATA": on that screen you will see the +B, IG SW and KEY SW values shown as NORMAL or ON.
4. Start pulling fuses one at a time while watching those three values: pull a fuse, wait a few seconds and, if nothing changes, put it back. Keep going until the value flips from positive (for example ON) to negative (for example OFF): that is the right fuse.
5. Do not waste time on the big fuses: the correct fuses are almost always the same rating as those fitted on the ZN067, typically 10A to 20A.
6. Then connect the ZN067 following the wire colours: the YELLOW wire goes to B+, the ORANGE wire goes to IG SW, the smallest wire is for the KEY SW.
7. Always confirm every connection made in the software: if something is wrong the software flags it and you have to check point by point.

Reference screenshots