Fuel pump wiring at hat.

Laga

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A11EC3E8-70C8-44F5-8F4C-E934FD0B8E41.jpeg I was repairing the wiring to the fuel pump hat. There are four wires. Two for the fuel level sensor,( Blue and Green) and two ( Red and Black ) to power the pump.
All wires were inside a convoluted tube. The blue and green wires were loose and separate. The red and black wires were twisted together and covered with tape. When I cut back the tape on the red and black, there was an uninsulated stainless steel wire in the bundle (see photo).
Is this wire for reinforcement, or is it part of the grounding system of the pump? I couldn’t see if it was spliced into either wire after cutting into the twisted bundle. It’s difficult to see everything because I cannot get into the back seat of the car due to a hip injury.
 

Midlife Crises

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The bare wire is part of the shielding (the foil wrap) and should be grounded at one end I believe.
 

Laga

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The bare wire is part of the shielding (the foil wrap) and should be grounded at one end I believe.
Thanks, that’s what I thought, but I wanted to make sure. Don’t want to do this more than once.
 

JeremyH

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It is just noise/emi shielding, it does not need grounded.
 
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redfirepearlgt

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It does need to be grounded according to the prints I have. It is a shield to inhibit induced noise that comes from the motor which could induce noise into the wiring going to the gauge from the sending unit. The shield is ONLY shielding the pink/blk and black wires that go to the pump motor. The shield is tied ultimately to chassis ground. Reference page 24-8 of the 2005 wiring diagrams manual. It shares common ground with the FPDM. The two ultimately ground in the back of the trunk just right and above the license plate mounting area (from the inside). See image below for grounding point.
FGmknqs.jpg
 

Laga

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Thanks a million. That's exactly what I needed. When I cut the bundle that contained the black, pink/blk, and bare wire, it just so happed to be at the point where the bare wire ended, so I couldn't tell if it was connected at that point. Plus, there was a lot of corrosion from road salt. I can check to see if everything is grounded properly now.

Im still having a problem with the fuel gauge. It`s been a year or two and I would like to get it fixed. It will read full, but then, it will not go down any lower than 3/4. The amount of fuel used in the info center is 100% correct. I replaced the stepper motors on the instrument panel about ten years ago. The other gauges work fine. Ever hear of the replacement stepper motors going bad? I pulled and measured resistance of both fuel level sensors and they are OK. I know the fuel level sensors go to the SJB. There has never been a problem with water leaks. I do have a couple of accessories (temp and A/F gauges) plugged into the fuse box under the SJB with "add a circuit" piggyback fuse plugs. I believe a aftermarket remote starter gets it power there also. Could these be interfering with signal to the fuel gauge? I plan on pulling these and see what happens.
 

JeremyH

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Thanks a million. That's exactly what I needed. When I cut the bundle that contained the black, pink/blk, and bare wire, it just so happed to be at the point where the bare wire ended, so I couldn't tell if it was connected at that point. Plus, there was a lot of corrosion from road salt. I can check to see if everything is grounded properly now.

Im still having a problem with the fuel gauge. It`s been a year or two and I would like to get it fixed. It will read full, but then, it will not go down any lower than 3/4. The amount of fuel used in the info center is 100% correct. I replaced the stepper motors on the instrument panel about ten years ago. The other gauges work fine. Ever hear of the replacement stepper motors going bad? I pulled and measured resistance of both fuel level sensors and they are OK. I know the fuel level sensors go to the SJB. There has never been a problem with water leaks. I do have a couple of accessories (temp and A/F gauges) plugged into the fuse box under the SJB with "add a circuit" piggyback fuse plugs. I believe a aftermarket remote starter gets it power there also. Could these be interfering with signal to the fuel gauge? I plan on pulling these and see what happens.

No the level senders operate on a resistance circuit so would have no effect on it.
 
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JeremyH

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It does need to be grounded according to the prints I have. It is a shield to inhibit induced noise that comes from the motor which could induce noise into the wiring going to the gauge from the sending unit. The shield is ONLY shielding the pink/blk and black wires that go to the pump motor. The shield is tied ultimately to chassis ground. Reference page 24-8 of the 2005 wiring diagrams manual. It shares common ground with the FPDM. The two ultimately ground in the back of the trunk just right and above the license plate mounting area (from the inside). See image below for grounding point.
FGmknqs.jpg

There was some ambiguity in your statement and I realize there was in mine as well. It doesnt need grounded at the fuel hat plug. Ie he doesn't need to create an additional ground for the shielding when he connects the new fuel hat connector is what I was trying to convey.
 
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