99 Grand Prix blowing relays


#1

A friend of mine has had a problem that over the last five years has gotten worse and worse and now the car will barely start without getting a new relay. The fuel pump relay blows or wears out to the point it seems like the engine will not turn over at all. Help Me Please! look good to her!


#2

For the fuel pump relay to burn out, excessive current is going through it. Somewhere, between the relay and the ground on the other side of the fuel pump, there is a low resistance (“partial short”) in the wiring or the fuel pump.
Use the wiring diagram, and a multimeter, to check the circuit from the relay through the fuel pump for power going to ground through wiring or through the fuel pump.


#3

I agree with Hellokit about the excessive current draw. One thing you can do to prove that is to remove the fuse that ties to the pump and check the current across the fuse position contacts. You will be able to see how much is being drawn. I would guess a normal draw is about 4 to 5 amps. The pump motor may not be able to turn as fast as it should be or perhaps there is some shorted windings in it. These things will cause excessive current to be drawn by the motor. You will need to replace the pump if there is a problem.