lift pump ground where is the other end ?

[jimbothe3]

I loved to know where the other end of the ground from the lift pump is located ??? lift pump has power but not ground, had new trans installed and wondering if the ground is any where near or supposed to be by the bolts, for it ran funny since install, was thinking water in fule so turned t handle to drain out truck stalled wont restart so I found lift pump not working, and checked wires to find out not grounded... I read many post and not found this info,,,,, 1999 6.5 turbo 4x4 extended cab older body non 3 door GMC

[Warren96]

Try running the pump on an external 12 v source ...... first mark the positive wire so that you don,t hook it up backwards!!!!! The wiring circuits on the lift pump varied from year to year.

[More Power]

The GM service manual states that: "For illustrations and ground strap locations, refer to Ground Distribution in Electrical Diagnosis."

Unfortunately, I don't have the electrical diagnosis manual for the 1996+ trucks. However, the 1998 GM service manual that I do have specifies that the ground circuit connection for the electric fuel lift pump is identified as G404.

The G10x series of grounds are mostly under the hood or radiator core support for things like headlights and the engine. G20x ground circuits are beneath the dash for systems such as HVAC and IP cluster, etc. So, ground G404 must be located somewhere near the rear half of the vehicle (there are no G50x series of grounds).

So... I'd look for G404 on top of the driver's side frame rail near the fuel tank. Should be an electrical eyelet with a black wire that is bolted onto the frame rail using a small bolt.

Let us know what you discover.

[racer55]

The LP ground should be very near the LP fastened to the frame of the truck-common place for corrosion or debris damaging it.

Might be behind the fuel tank but can't say-you need to look in that area and trace the wire back to the origin.