Originally Posted by martysmartie

It won't illuminate seen as there is no supply!

Pin 28 is the ground for the relay, input from the CPS is required for the pump to prime, in addition, the duration of the prime can vary with temperature.

It has nothing to do with the phase sensor, this as the name suggests gives information on the 'phasing' of cylinders, used for SFI.

I am guessing it has not always done this?

Martin