On my 95 +8 the inertia switch is wired so that
In normal position the power feed goes to the pump.
When the switch is activated the power feed to the pump is broken and power is now fed to a lamp in the cluster above the steering column.
That is why there are three wires.
Took me about 10 years before I tested the switch and found the warning lamp on
Originally I thought that lamp was a MIL light, but have found the MIL light feed from the ECU isn't wired. I have modified the ECU code and wired up a MIL light, but that's another story
