Died while driving, now crank-no start

[Nightowl]

how did you measure the 12v? Any working motors should run at 12v supply.

Unplugged the pump and used a multimeter while I turned the key to the second position. Once I confirmed that it was getting power/ had ground, I plugged it back in and with a hand on top of the pump, turned the key to second position.

The pump kicked briefly, but did not fully prime/ run. So my thought was that it might be getting 12v initially, but as soon as there's an actual load going through the system, the relay trips.

[sapote]

Unplugged the pump and used a multimeter while I turned the key to the second position. Once I confirmed that it was getting power/ had ground, I plugged it back in and with a hand on top of the pump, turned the key to second position.

The pump kicked briefly, but did not fully prime/ run. So my thought was that it might be getting 12v initially, but as soon as there's an actual load going through the system, the relay trips.

1. you measure the volt between the two wires (going to the pump) and not from one wire to the chassis ground? Have to measure between the two wires.
2. I'm confused. You first said there was 12v during the priming time, then why you think the relay trips or fails? If relay trips then you don't have 12v

To do: with cable plugged to the pump, measure the voltage between the 2 wires and it should have 12v continuously during the 2 or 3sec priming time. Measure the wires with pump disconnected is useless.