Admin Table of Contents
How do you know if a relay is out?
The only tool required to check a relay is a multimeter. With the relay removed from the fuse box, the multimeter set to measure DC voltage and the switch in the cab activated, first check to see if there are 12 volts at the 85 position in the fuse box where the relay plugs in (or wherever the relay is located).
What would cause a fuel pump relay to go bad?
The most common cause of a fuel pump relay going bad is electrical power surges that increase the voltage. The fuel pump relay is designed to have a winding that causes contacts to pass current or voltage. In some cases, the current or voltage might be so high that the contacts get burned.
How to tell if a fuel pump relay is bad?
No noise from the fuel pump Another symptom that may point to a bad fuel pump relay is no noise from the fuel pump when you turn on the ignition. The fuel pump is located in the fuel tank, near the rear of the vehicle and can usually be heard when the engine starts.
What happens if you have a bad fuel pump?
This indicates a problem with the fuel filter, fuel pump or fuel relay. A faulty fuel pump relay can cause the car to come to a complete stop while driving. This will not be instant, but it may resemble what happens when a car runs out of gas. The vehicle will gradually slow to a stop and the engine will refuse to come back on for a time.
How does the fuel pump relay control the car?
The fuel pump relay is usually controlled by the ignition or powertrain control module, and when switched on, will provide current to the fuel pump so that it may function. As the fuel pump relay controls power to the fuel pump, any faults with it can cause issues with the fuel pump, which can cause drivability problems for the vehicle.
What kind of noise does a fuel pump make?
No noise from the fuel pump. Another symptom that may hint at an issue with the fuel pump relay is no noise from the fuel pump when the key is switched on. Most fuel pumps will produce a low volume hum or whine which can be heard from the inside the vehicle if listened for closely, or from the outside of the vehicle, near the fuel tank.