Aux output on continuously

[iceman]

1990 Nissan 300ZX LS conversion. G4+ wire in. 

I have a fuel pump being triggered (low side) through an aux output using the OEM wiring/relay.  The relay is supplied with a  continuous high side power supply, which I believe is normal for Nissans of this era. The problem is that the fuel pump runs continuously, battery and harness A connected but with the ECU otherwise totally electrically disconnected. There is continuity on the trigger wire between the ECU and relay.

This obviously sounds like a back feeding issue but in this case instead of power remaining up through the ECU issue, it appears to be an earth channel staying active on the aux concerned. Before I put in an extra relay on the OEM relay high side, do the aux channels normally go to a closed (on) position when the ECU is powered down to explain this issue?

Cheers.

[DerekAE86]

I'm fairly sure this is normal. You should wire the high side of the pump relay to a switched 12v source.

[Adamw]

The aux is not going low, your hot 12v fed is going into the aux and trying to power up every other device that is connected to an aux and the eccs circuit.  If you have a spare ignition drive the you can use that instead of an aux as it can’t back feed.