How do I wire updated fuel pump harness?

MVANN74

MEMBER
1997 CADILLAC SEVILLE
4.6L
V8
2WD
AUTOMATIC
135,900 MILES

On the above car I am attempting to replace the fuel pump. The harness on the old pump is a square 4 pin. The new pump has an oval 4 pin. The wires are the same color from the car and also the new pump. There are 2 black wires. One of the black wires is a thicker gauge. Then there's a purple and a gray wire. Please see pics below. I'm thoroughly confused. Please help. New harness is on left. Old harness is on right.

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Thursday, January 6th, 2022 AT 12:49 PM

3 Replies

JACOBANDNICKOLAS

MECHANIC
110,053 POSTS

Hi,

I don't ever remember seeing a fuel pump need wiring changed like this. Are you sure it is for the correct vehicle? I'm concerned simply because of the location of the connector. If there is any spark due to a connection issue, that may create an issue.

Next, I need to see both the plug and the connector on the pump. If I have both connectors with what each wire is for, I should be able to figure it out for you

Let me know.

Joe

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Thursday, January 6th, 2022 AT 5:31 PM

MVANN74

MEMBER
65 POSTS

GM part #19332090 is the one required for the replacement fuel pump on a 1997 Cadillac Seville STS. According to GM it requires an updated harness which was included with the new
fuel pump. The instructions that came with it are not very clear. Matching the wire colors doesn't work.

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Thursday, January 6th, 2022 AT 8:54 PM

JACOBANDNICKOLAS

MECHANIC
110,053 POSTS

Hi,

If possible, take a pic of the directions and upload them for me to see. Between them and the wiring schematics I have, hopefully, I'll be able to figure it out for you.

I attached a pic below from the schematic. Which wires (colors) were on the old harness?

Let me know.

Joe

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