Baja 232 w a 502 mag mpi.
I am getting 1.4 volts to pump. It’s not turning on. When I turn the key I don’t hear the beep along with pump turning on. I just put 2 brand new harnesses in it this weekend. My pump relay has 12v and the grey wire only has 1.4 I would think it would be much higher. Pump turns on if I hook it straight to 12v. Also not sure what these wires are for. I didn’t have them on my old harness.

Motor serial number?

502 Mag MPI HJ 1996–2001, 6HJ

is there a grey cap on a plug with 3 fuses inside one is for the fuel pump ? if this an OE wiring harness

Yes grey plug has a cap

1996 to 2001 goes across 2 manuals, not a lot of help

The single wire Blue/Tan (if it is tan) would be for transmission over temp (you don't have)

2 prong connectors
Unknown because unable to find anything in diagrams using those colors at rear of motor

Note fuses 15, 16 and 17
The fuel pump has a ground and Gray going to power up when relay energizes.

Ignition ON, supplies power to MPR. The MPR contact gets power from the engine circuit breaker thru a fuse and Red wire. The MPR is energized via the engine harness to EFI harness thru a pink wire

MPR supplies power to ECM and fuel pump relay contact. FPR is energized by the ECM thru the Green/White wire

Since your not getting a beep, then the beeper may not be connected and/or your not getting power to the ECM

Wires are the same but would probably have all 3 fuses under one cap 13

Has all three fuses under box. Relay is getting 12v through pink wire. Grey wire is only getting 1.4v. What is MPR?

Main Power Relay

How do I check that?