No power to new fuel pump?

2003 CHEVROLET SUBURBAN

100,000 MILES • 5.2L • V8 • 4WD • AUTOMATIC

RUSSR

MEMBER
1 POST

Replaced fuel pump. No power to fuel pump or fuel level gauge. Fully charged, good battery, good fuse, swapped relay with known good relay. Checked harness from PDC to fuel tank, no issues found. Reset security function. Security dash light off.

Nov 29, 2022 at 6:14 PM

JACOBANDNICKOLAS

✓ASE Certified Mechanic
110,194 POSTS

Hi,

I attached a wiring schematic below of the circuit. Note that the schematic is for dual tanks. I focused on a single-tank vehicle.

You indicated the relay is good. How was it checked? I ask because the relay can be good, but there are two separate power sources that need to go through it to work. One is provided by the PCM and the other is from the PCM B fuse in the under-hood fuse box.

Take a look at this link. It explains how to test a relay circuit.

https://www.2carpros.com/articles/how-to-check-an-electrical-relay-and-wiring-control-circuit

Let me know if you have already done this or what the results are.

Take care,

Joe

See pic below. Please ignore pic 1. I added it by accident and can't get it removed.

Images (Click to enlarge)

Professional Diagram for 2CarPros Members
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Nov 29, 2022 at 9:06 PM

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