Fuel pump relay

[Wayne Langston]

When I turn my key on the fuel pump relay buzzes and the truck won’t start . Checked the ground wire and even replaced the relay , the new one did the same thing . Any help would be appreciated .

 

[Curious Hound]

Sounds like the coil isn't getting full 12 volts probably from a loose or corroded connection. If your truck has an inertia switch, that's another place the connection could be bad.

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[tomw]

A relay that buzzes is not being fed enough juice to keep the relay contacts closed. The contacts close, the voltage available drops, the coil opens due to lower volts, the voltage recovers as the 'load' is gone, the coil closes again, the volts drop as the load is re-applied, rinse repeat... Bzzzzzzzzzt.
Your voltage is lacking, or your current capacity is down. The ignition switch could be faulty, the grounds on the relay bad(though they are mostly grounded by computer if computer controlled, so it would be battery voltage not ground)
What is your battery state of charge? Resting voltage?
tom