DIAGRAM FOR RELAYS LAYOUT

yes . i was looking at 3 relays on diagrams that u provided and i got confused why on lasT relay fuel pump, on pin 85 ECU, ON RELAY FOR FUEL PUMP IS IT GROUND RIGHT TO ECU.

I don’t remember that diagram very well but I know the ecu sends the signal as signal ground. So that might be why in order to trigger the relay on.

Hi Omy,

Most ECU's wont be able to provide the 12v required on pin 86 to activate the relay.

However they are able to pull the 12v to ground(or in other words turn 'on' a ground signal) on pin 85 - so you'll find a lot of relays are switched at ground(pin 85) rather than on positive (pin 86)

Cheers,

Merlin