On my 1990 GMC Sierra, I recently installed a.

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MEMBER
1990 GMC SIERRA
188,945 MILES

On my 1990 gmc sierra, I recently installed a new fuel pump, and I jumped the relay to see if the pump would run, and when I did, I jumped the wrong two prongs on the relay connector, and shorted the connector. I spliced a new connector in and now im getting power to the fuel pump, just not the needed 12 volts. Ive talked to a few mechanics and they've said that i've fried a ground. Can someone tell me where the ground would be located? Or is there anything else that could be wrong. Any help is greatly appreciated.

Wednesday, January 9th, 2013 AT 6:16 PM

1 Reply

JDL

MECHANIC
16,098 POSTS

There should be an oil pressure switch in the fuel pump circuit. Once you crank it enough to bring up the oil pressure, the switch closes, sends voltage to fuel pump. Even without the relay. There is a fuse close to the fuel pump relay, check that fuse, also check for voltage at the fuse. You can check the ground for the relay by using a testlite connected to battery voltage, If the ground is good, the lite comes on. At the relay, I believe the ground is black. Let us know what you find.

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Wednesday, January 9th, 2013 AT 6:57 PM