Fuel pump relay orange wire faking ground

1987 Canadian VDP V12.

In this abridged diagram, the orange wire is, I believe, a switched ground. If I jump between 30 and 87 on the fuel pump relay, the pump will run… but even runs with the ignition off :(. The pink wire KB is hot when the car is in run (as per the blue circle).

So, I think the orange wire doesn’t ground out. If I just manually and permanently ground pump relay position 85, 86 will still be dead with the ignition off and the relay will still basically function Right?

[quote=“John6, post:1, topic:351904, full:true”]
1987 Canadian VDP V12.

In this abridged diagram, the orange wire is, I believe, a switched ground. [/quote]

Right, the ECU switches the ground on-off

Right, because the brown wire to terminal 30 is constant battery voltage

Right

[quote]
So, I think the orange wire doesn’t ground out.[/quote]

Common problem with the V12 ECUs

[quote]
If I just manually and permanently ground pump relay position 85, 86 will still be dead with the ignition off and the relay will still basically function Right?[/quote]

Yes. but the pump will run whenever the key is ‘on’…which is not ideal from a safety standpoint but, if you decide to do operate the circuit that way I can assure you that you wouldn’t be the first :slight_smile:

Cheers
DD