Need a tiny bit of help, I'm installing the BOE surge tank and am at the wiring step. The instructions state to splice into the black wire of the inertia switch so that the tank's pump doesn't operate in the event of an accident. However, the connector into my inertia switch (2008 Exige S240) has three wires, two purple, and one smaller white wire in the middle. Anyone know which wire I should tap?