There's NO SUCH THING as a separate "starter interlock switch"!!!PoisonDrop wrote:True, but what's the point?
Look at it this way. Both the neutral switch and the clutch switch ground a brown/yellow wire when active. These two brown/yellow wires are connected to each other, therefore both switches ground the same pin on the ECU, essentially bypassing one when the other is activated. So the switch, in this case, is completely redundant. The ECU can't tell the difference. It only cares that the gears aren't engaged, not how they got that way.
Plus, like I said, the clutch switch in that diagram has nothing to do with starting the car. It is pointless to bypass it. You must bypass the starter interlock switch, which is a totally different circuit. That is why I believe a relay is absolutely necessary, especially because of the current that the starter interlock switch handles (40A, judging by the wire gauge used).
The proper name of the clutch switch is "starter/clutch interlock switch".
The wire that in the diagram is interconnecting the clutch and neutral switches HAS TO BE A MISTAKE, because if that wire existed you could start the car in neutral without depressing the clutch, which we all know DOESN'T HAPPEN.
So, yeah, the ECU CAN tell the difference, because the neutral switch goes to the ECU, while the starter/clutch interlock switch goes to the cruise control module.