Fuel pump voltage

2002 GMC SIERRA

100,000 MILES • 6.0L • V8 • 4WD • AUTOMATIC

D SCHEIDEL

MEMBER
1 POST

Have replaced multiple fuel pumps in recent years, also replaced wiring connector at pump. Reconnected all grounds when I checked supply voltage at pump it was only 5 volts. Seems like that would explain the pumps burning out so quickly. Traced the power lead back to engine bay and to a module near the battery only read 5 volts everywhere I checked it.

May 21, 2019 at 6:37 AM

SCGRANTURISMO

✓Experienced Mechanic
4,897 POSTS

Hello,

Okay. Can you get me a voltage reading at pin #87 of the fuel pump relay in the underhood fuse block of your vehicle. You will need to have an assistant cranking the vehicle or have the vehicle running while you are getting the reading. I have included a wiring diagram of your vehicle fuel pump circuit with the wire from the relay to the fuel pump hilited. I have also included a diagram and call out of the underhood fuse block for you in the diagrams below. Get back to us with what you are able to find out please.

Thanks,
Alex
2CarPros

Images (Click to enlarge)