I have a 2003 pontiac grand am, getting no fuel, pump won't run. I put in a new pump, filter, and changed the relay. Sometimes the pump will kick on and i can start the car, but not today. Took apart the fuse box and could see no visible problems inside. Any ideas?

welcome to AF.

I'd inspect the fuel pump wire harness,
that's probly where the short is....

....you did check the fuel pump fuse ??

I changed the wire harness, forgot to mention. It's getting no power from the fuse box, i tested. I just got it to start a few minutes ago, but i can't repeat the miracle. I get a buzzing sound from the relay, that's it. The fan doesn't want to work either. Any other ideas?

The relays are good, and once it's running, it stays running.

Did you "replace" the relay or did you just swap it with another ?

It has to be the relay/fuse or a broken/bad wire if its getting no power to the fuse box/ f pump.

Your security light isnt flashing or ON is it ??

I took the relay from the horn (which matched). The security light only is on (not flashing) when you turn the key on, along with most of the other lights in the instrument panel. Could it be a sensor, or the ignition?

I know I should buy a new relay, but i've actually tried several of the other ones in there on it. By testing wires, i've pretty much ruled that out as the source of the problem. I can't find any bad wires, but i'll keep looking.

Sometimes when installing the fuel pump wire can become disconnected. If nothing else pans out might give that another look.

Also the horn relay may not be the same even though it looks the same.
These are not like older cars where several relays are the same and can be mixed and matched. And can toast a good relay real quick.

I'd start at the fuse box and trace the power back to the pump. Since its intermitant it is going to be tough to track down.

Btw have you verified the fuel pressure ?
Could even be your fuel pump regulator. ;)

Thankyou, i assumed the relay would swap, because it had the same numbers. Where is the pressure regulator located?

If the relay was identicle then I'm sure thier wasnt an issue with the swap.

The fuel pressure regulator is on the front fuel rail, drivers side. Has 1 vacuum line connected to it.

The schradder valve is on the pass side, rear fuel rail.
The valve is between the power steering pump and alternator.

This could also be the wire harness for the fuel pump, I know you replaced it , i'd double check the connectors.
It does happen once in a while when replacing the fuel pump wire harness.

Is there any way to test if the schradder valve or fuel pressure regulator are not working properly?

Yeah, rent or buy a fuel gauge tool, sold at most part store(s). Fuel pressure should be 41-47 PSI with the key "on" engine off.

Since you havnt mentioned your engine and mileage....
... if your car is a V6 it'll have a valve to check the fuel pressure.
The 4 cyl, does not have a valve to check the FP,
you'll need a different adapter/hose with a guage that's installed in the fuel line.

Also sometimes when the fuel pressure regulator goes out,
if you disconnect the vacum line, fuel will come out of the hose indicating the fuel pressure regulator bad.

Being your GA is a 2003 I would not have thought the fuel pump,
or the regulator would be bad just yet..

.. but things do very due to geographic location.

It has no fuel pressure at all. If I can ever get the pump to come on again and start the car, i'll drive it to a shop. If I knew where the power came from before it got to the fuse box, i might could trace it back, but i'd just be guessing.