How to test a fuel pump relay with a multimeter?

1 Turn off your vehicle and remove the key from the ignition. 2 Find the fuel pump relay in your vehicle’s fuse box. 3 Pull the relay straight out from the fuse box to remove it. 4 Clean the relay prongs with a wire brush. The fuel pump relay may be faulty or have a loose connection if it’s developed any rust or corrosion on the …

Is there a problem with the fuel pump relay?

If you notice a problem with your fuel pump, such as no noise coming from it or your engine not starting, there could be a problem with the fuel pump relay, which controls the electric current running through the pump. Luckily, fuel pump relays are easy to test and replace on your own.

What does a green fuel pump relay look like?

If it has already been replaced with an after-market one, this relay won’t be green, but will have a gray body. The following tutorial may be of help: How To Test The Fuel Pump (Ford 4.9L, 5.0L, 5.8L) (at: troubleshootmyvehicle.com ).

Is the fuel pump relay controlled by the PCM?

Consequently, the fuel pump relay is usually controlled by, the ignition or powertrain control module (PCM). As a result, when switched on, the fuel pump relay; will provide current to the fuel pump, so that it may function. Therefore, any faults with it, can cause fuel pump issues.

How do you check fuel pump?

Checking fuel pump. There are two methods of checking the fuel pump. One of the method includes the use of an electrical test. The steps include; Checking the pump fuse. Check the voltage of your pump. Then perform a drop test by use of a voltmeter.

What are the symptoms of a bad fuel pump fuse?

Unusual noises, sputtering or backfiring may also be indicative of a bad fuel pump. If the flow to the fuel injection system in the vehicle is not consistent, the engine may develop problems. Watch for things like a hesitant start or take-off, or a problem with starting the vehicle.

What does a fuel pump relay do?

What Is a Fuel Pump Relay? Function. The engine control module (ECM) uses the fuel pump relay to control when the fuel pump is on. Location. Check your owner’s manual for the location of your fuel pump relay. Function. Malfunctions. Considerations.

What is a fuel relay?

A fuel pump relay or any kind of relay is an effective way to utilize a small degree of voltage to generate a signal in order to open or close the contact of a higher current or voltage line. The relay basically functions as a switch.

What to do if your fuel pump relay is short?

If you detect zero ohms or any resistance value instead of infinity, your fuel pump relay has shorted power pins and needs to be replaced. Set your digital multimeter to ‘continuity’. Connect one lead to one of the power circuit pins, and connect the other lead to the other power terminal.

What do I need to bench test a Ford relay?

You’ll need two very important things to bench test the Relay and they are: Multimeter The Multimeter can be digital or analog multimeter. If you need to buy one or are looking to upgrade, check out my recommendations here: Buying A Digital Multimeter For Automotive Diagnostic Testing.

How many pins does a fuel pump relay have?

Generally there are four pins (terminals) on the fuel pump relay. One is for input voltage, one is the ground pin, one is the load pin that goes to the fuel pump, and one goes to the battery.

How many terminals does a fuel pump relay need?

Once you know how to test a fuel pump relay, you can test other automotive relays without much trouble. You’ll find relays with three, five or even six terminals, though. On three terminal relays, the case itself may serve as the ground connection.

What kind of multimeter do I need to test a NC relay?

Use a digital multimeter (DMM) or analog ohmmeter to measure the resistance across the load connections of the relay. The reading should be open (infinite ohms) on an NO relay and short (0 ohms) on an NC relay. DMMs and analog ohmmeters are available in electronic parts and hobby stores.

How to test a fuel pump relay with a multimeter?