How to switch on the separator relay?

One 6.3 mm pin of the relay is connected to D+ (alt 61 or STA) or to the appropriate pin on the ignition switch. (The ignition switch uses the pin that is energised when the engine is running, but not when the engine is off.) This wire controls the relay.

The other pin is connected to the negative (-) of the starter battery, preferably using 2.5 mm2 cable or larger.

All the relay connections are polarity independent, which means that there is no risk of connecting the relay or the relay control “backwards”.

So just choose which pin you want to use for plus and minus.