Fuel pump trouble shooting, Iv'e replaced the relay and don't get a reading on my VOM with the ingition on and the probes on the pump power and ground. Didn't get a reading with the old relay either. Is there another fuse or relay location? I replaced the one on the left in the glove box

In most cases, the primary symptom is a check engine light.And you know what this means right? It’s a sign the ECU is holding on to some trouble codes. In order to read the code, you’ll need to hook up an OBD2 scan tool. If you find a P0230 or P0231 OBD2 Diagnostic Trouble Code (DTC), this means a malfunction in the primary circuit of the fuel pump.

The fuel pump relay should be under the hood on the firewall, square with a 3 in it. Hope you can read it?

there cud be a module-those cars are complex--send issue to [email protected] a master on any make and model

Do you have a test light? If not, go buy a cheap $5 test light-one with a lead to clip to a ground, and with a needle type probe.
Pull the fuel pump relay out of the terminals it is plugged into-you need to check if the power feed for the pump is still available at the relay. Clip the test light lead to a ground and touch the test probe to the positive battery post-to check that your ground is good- tester should light up. Now touch the probe to all of the terminals that the relay plugs into. One terminal should have power with key off. If no terminals have power, you have lost the power feed for the pump. Double check all your maxi fuses in the power distribution box. Either a maxi fuse or a fusible link will be the power feed for the fuel pump relay.
If the power feed is there at the relay, try a new relay. If still no pump, a shop will probably have to check your fuel pump circuit.
Did you check for power at the fuel tank while the key was held in crank? When the engine is cranking, the fuel pump wire should have power. When the key is turned to on, the fuel pump should have power for about 2 seconds, to pressurize the fuel system. Then when key is turned to crank or start, the fuel pump should stay on.

Hot wire it! Set a battery by rear of car and run jumper wires to the fuel pump connector.. Instant gratification !
You could almost do the same thing at the fuel pump relay with one short jumper wire: pull the relay out and jump the battery power feed there across to the fuel pump wire. Turn key on and pump should run. Be careful, make sure you do have a single hot line at the relay with key on, and don't put the jumper wire in the wrong slot, or there won't be anything left to play with. You'd have to know which terminal was the fuel pump wire leaving there and going to the pump.
Well, there are a couple of shadetree solutions, worked for me. I assumed from your post that you probably don't have a voltmeter, which if true, is only bad if you want to do any work on your truck yourself. 'Cuz taking the tank off is a thankless, dirty job, and a voltmeter could have saved the trouble by testing for power at the fuel pump connector when the engine was being cranked over. If the wire has power, only then would you know the pump has to be taken out. Good luck.

Did you do it like this? Voltmeter: black lead on negative battery terminal, positive lead on one of terminals on coil side- turn key to on, and see if there is voltage for about 2 seconds. If yes, check negative terminal of relay's coil side. If no voltage, move positive lead to other terminal for coil side. Turn key to on, and see if you have voltage for about 2 seconds. If yes, test negative side of relay's coil for good ground. If no signal at either terminal, the signal may be lost from the pcm.

When you turn the key to on, this will prime the fuel system-pump will turn on for only 2 seconds with key in on, and then if no crank signal, pump will turn off (the relay will not stay energized, so no power will go to pump). But when the engine is cranking over, the relay is energized, the coil side will stay powered as long as engine is cranking. After the engine is running, usually an oil pressure switch is tied into the fuel pump circuit, so the relay is no longer needed to put power to the pump. The pump will always be running when engine is cranking, and when engine is running, but the relay no longer is needed when engine is running. See?

check for broken wire's in fuel pump relay circuit a test light works good with a sharp point on it so you can perce wire and narrow down were the beark might be but always check the place's that could be exposed to the element's first

The computer cannot tell if the pump is good or not. A failed pump will not set a trouble code,
Here's how to check if it's a bad pump or an electrical wiring issue: Unplug the fuel pump connector at the gas tank. Use a testlight or a voltmeter there, and make sure the testlight or voltmeter is grounded good on a bolt or piece of metal. Then check the fuel pump wire with the testlight probe or with the positive probe of voltmeter on the body harness side of connector, while someone cranks the car.
See? You are looking for 12 volts steady current at the fuel pump wire by the tank when car is cranking over. Sometimes hard to get a good ground on tester there with all the dirt and crud, but keep trying till you are sure you either do or do not have power to pump when engine is cranking. If you do find power there, then the pump is bad and needs to be replaced. But if you don't have power there, then the wiring to pump needs to be diagnosed, because something is not turning pump on as it should. The computer is tied into the relay and turns the pump on there. In most cases it is a bad pump, but checking the wire at the pump will tell you for sure.

Your GM car or truck has a relay to turn the fuel pump on and off. The fuel pump pulls gasoline out of the tank and sends it to the engine. If the relay fails, the pump won't come on and the engine won't start. Since many things other than a bad fuel pump relay can cause a car to not start, you need to remove it to test it properly. Look for your GM relay in the fuse box under the hood that contains fuses and circuit breakers.
Open the hood of your vehicle and find the relay. If your fuse panel isn't labeled, look in your owner's manual for the specific location. With the ignition off, pull the relay out of the socket. You might need to wiggle it a little to get it loose.

2 Look on the relay for the pin designations. Most relays have a diagram printed on the cover. If not, look in a service manual or wiring diagram for your GM vehicle. You need to identify the two pins for the coil and the two pins that the relay closes to turn on the fuel pump, usually marked "common" (C) and "normally open" (NO).

3 Turn your multimeter dial to an ohms scale and touch the tips of the probes together to test it. The meter should read zero ohms.

4 Touch the probe tips to the pins that connect to the relay coil. The meter should read between 50 and 120 ohms. If not, the relay coil is bad.

5 Touch the meter leads to the two pins that should make contact when the relay operates. You should not read anything at all on the meter, indicating that the terminals aren't making a connection. If you read ohms, the relay contacts are stuck or shorted.

6 Connect one end of each test lead to each of the two pins connected to the relay coil. Connect the other end of one of the test leads to the chassis ground and the other to the battery positive terminal. The relay should operate and you should hear a click.

7 Touch the meter probes again to the two pins that should make contact. They should now read zero ohms, indicating that the connections are making contact. If not, the relay is bad.

Hi, the relays should be in the box under the hood. Check the INJ fuse and the PUMP fuses. If those are good, interrogate the relay socket using a voltmeter or 12 volt test light. Connect the test light clip or voltmeter probe to chassis ground and probe the relay socket. With the key off, there should be one hot terminal. With the key on, there should be 2 hot terminals. If not, the MAIN RELAY is not coming on and you will need to interrogate that relay socket as well. If there are 2 hot terminals in the PUMP RELAY socket with the key on, move the test light clip/probe to battery positive and probe the socket again. You should get similar results from the other 2 terminals in the socket. The pump terminal may be only a dim light, but the terminal from the ECM should be a bright light/battery voltage. If not, the ECM is not turning the relay on--possibly due to the anti-theft system or some other safety feature. Please let me know if you have questions, and thanks for using FixYa.