Where is fuel pump relay switch? - 1998 Chevrolet Malibu

Hey James , It's in the under hood fuse box , F/PMP relay an there is a fuse F/PMP 15 amp. Underhood Accessory Wiring Junction Block
Right side of the engine compartment, mounted to the strut tower

The PCM controls the fuel pump relay by supplying switched ignition voltage to the fuel pump relay coil. When the ignition switch is first turned On, the PCM energizes the fuel pump relay. The relay contacts close applying power to the fuel pump. The fuel pump relay will remain On as long as the engine is running or cranking and the PCM is receiving reference pulses. If no reference pulses are present, the PCM de-energizes the fuel pump relay within 2 seconds. With the engine stopped, the fuel pump can be turned On with a scan tool.
If the PCM detects a problem on the relay control circuit, DTC P0230 will set. Use this table if DTC P0230 is not set and a problem exists with the fuel pump!

This should be in the owner's manual. I found the below on autozone.com, their repair help location:
An inertia switch is used as a safety device in the fuel system. The inertia switch is located in the cab, generally under the dashboard on the right side. It is designed to open the fuel pump power circuit in the event of a collision. The switch is reset by pushing each of 2 buttons on the switch simultaneously (some models use switches with only one reset button). The inertia switch should not be reset until the fuel system has been inspected for damage or leaks.
When the ignition switch is ON , it turns the EEC power relay ON . The EEC power relay provides power to the powertrain control module (PCM) and the control side of the fuel pump relay. Power for the fuel pump(s) is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flows through the fuel pump relay and inertia switch to the fuel pump(s). The fuel pump relay is controlled by the PCM.
When the ignition switch is turned ON , the fuel pump(s) will operate. If the ignition switch is not turned to the START position the PCM will shut the fuel pump(s) OFF after 1 second. The PCM will operate the fuel pump(s) operate the fuel pump(s) when the ignition switch is turn to START position to provide fuel while cranking.
After the engine starts, the PCM will continue to operate the fuel pump(s) unless the engine stops, drops below 120 rpm or the inertia switch is tripped.

9.5 volts sounds like the power coming from the gas gauge.
I am showing a relay module with the fuel pump and pcm relays built in along with two other relays. The fuel pump relay should not be accessable. In most cases the pump relay gets power from a 20amp fuse and the computer grounds the relay when needed. Power goes from the pump relay to the inertia switch then to the pump. So the inertia switch should be hot when the pump relay is activated.

The fuel pump relay switch gets the fuel pump running in the vehicle during the start cycle. The terms fuel pump relay and fuel pump relay switch are used interchangeably.------------------------------------------------------------------------------------------
Super VAG K+CAN V4.8

A small but important part of your car's engine fuel delivery assembly, the fuel pump relay is an electrical component that controls the pump. Also known as a relay switch, this car part turns your fuel pump on and off when you start your vehicle and shut it off. Everytime you turn on your ignition, the relay switch lets the electrical current flow to the fuel pump. Once both the pump and your engine are running smoothly, the fuel pump relay automatically shuts off. The fuel pump will then be controlled by the oil pressure unit. In case your pump relay stops working, it's the oil pressure switch that will serve as a back-up power relay for the pump. Because the fuel pump relay is switched on everytime you turn on your ignition, you should hear a distinct sound (it could be like a whistling kettle or a blackboard being scraped) whenever you start your car. If you don't hear that distinct sound and your engine takes longer to crank up, you may have a problem with the relay switch. Fortunately, finding a compatible replacement relay for your vehicle is just a few clicks away at Auto Parts Warehouse. When you buy from our site, you can enjoy our free shipping services, low-price guarantee, and flexible payment options. So, if you need to replace your old relay switch for the fuel pump, buy one only from Auto Parts Warehouse!

No noise from fuel pump when you turn over the car .First thing get voltage at fuel pump relay checked, is there 12 volt to the relay.If no, then problem is again the relay.--------- To reconfirm the problem, try other test, that is remove the relay and by pass the relay terminals with a jumper wire .Then with 12 volt external battery give power to fuel pump connector and see, if the fuel pump starts, then its clear that fuel pump relay is faulty.----------- Also other problem can be fuel pump inertia switch.If the inertia switch is faulty then also fuel pump will not start.-------- The fuel pump relay on a 1995 Ford Explorer is in the power distribution
box, in the engine compartment, driver's side near the firewall.----------
The fuel pump inertia switch is in the right front passenger area
it is below the dash but above the carpet in the right hand corner.--------
Its a push button type inertia switch.
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Fuel Pump Activation
When ignition switch is turned to START position, PCM operates fuel pump relay to provide fuel for starting engine. PCM senses engine speed and shuts off fuel pump by opening ground circuit to fuel pump relay when engine stops or engine speed drops to less than 120 RPM. When ignition switch is in ON position, EEC power relay is energized (contacts closed). Power is provided to fuel pump relay and timer in PCM. Fuel pump receives power through fuel pump relay contacts.
Inertia Fuel Shutoff (IFS) Switch
All models use an electrical interrupt switch in fuel system. During a collision or vehicle rollover, electrical contacts within inertia switch open, shutting off fuel supply to electric fuel pump. Fuel supply is interrupted even when engine is running.
A reset button is located on switch assembly. If electrical circuit trips, vehicle will not restart until switch is reset. Fuel system should be inspected before resetting switch.
IFS switch is located under instrument panel, near right side of transmission hump. ----------- If the fuel pump relay, the inertia switch and fuel pump all checked ok, and fuel pump is working with direct 12 volt source to fuel pump.Then problem relates to computer.The computer (power control module, PCM) is faulty and has to be replaced.--------- This will help.Thanks.Helpmech.

There is a fuse for the fuel on the firewall inside the cab:




Fuel Pump The fuel delivery system uses either a high or low-pressure in-line or in-tank electric fuel pump, with some models equipped with both. It is a recirculating system that delivers fuel to a pressure regulating valve in the throttle body and returns excess fuel from the throttle body regulator back to the fuel tank. The electrical system uses two types of control relays, one controlled by a vacuum switch and the other controlled by the powertrain control module (PCM) to provide power to the fuel pump under various operating conditions.

An inertia switch is used as a safety device in the fuel system. The inertia switch is located in the cab, generally under the dashboard on the right side. It is designed to open the fuel pump power circuit in the event of a collision. The switch is reset by pushing each of 2 buttons on the switch simultaneously (some models use switches with only one reset button). The inertia switch should not be reset until the fuel system has been inspected for damage or leaks.
When the ignition switch is ON, it turns the EEC power relay ON. The EEC power relay provides power to the powertrain control module (PCM) and the control side of the fuel pump relay. Power for the fuel pump(s) is supplied through a fuse link or high current fuse attached to the starter solenoid (battery side). From the fuse link or high current fuse, current flows through the fuel pump relay and inertia switch to the fuel pump(s). The fuel pump relay is controlled by the PCM.
When the ignition switch is turned ON, the fuel pump(s) will operate. If the ignition switch is not turned to the START position the PCM will shut the fuel pump(s) OFF after 1 second. The PCM will operate the fuel pump(s) operate the fuel pump(s) when the ignition switch is turn to START position to provide fuel while cranking.
After the engine starts, the PCM will continue to operate the fuel pump(s) unless the engine stops, drops below 120 rpm or the inertia switch is tripped.

Did you check the fuel inertia switch in the passenger side kick panel ?

The fuel pump is powered :
the fuse to the fuel pump relay.
The fuel pump relay to the fuel inertia switch
The fuel inertia switch to the fuel pump itself.

At the fuel inertia switch in the kick panel, power from the relay is the Dark Green w/ Yellow stripe wire and the pink w/ black stripe wire is the power. from the fuel inertia switch to the fuel pump.

If you jumper the fuel pump relay, you should hear it run. If not pull the fuel pump relay, and check the pins in the relay socket, pin 30 should be the power from the fuse.



If you have power at pin #30, jumper the relay socket as shown with the red line above, and check the dark green w/ yellow stripe wire at the fuel inertia switch for power.
Press the button on the top of the fuel inertia switch, and check for power leaving the fuel inertia switch on the pink w/ black stripe wire.

This is tests good, check for power at the fuel pump, same pink w/ black stripe wire.
Fuel inertia switch info is in the owners manual, If you did not get an owners manual with your truck ( purchased used ), you can download one from Ford :
https://www.fleet.ford.com/maintenance/owners_manuals/default.asp

You could have a bad fuel pump relay switch. The fuel pump relay switch gets the fuel pump running in the vehicle during the start cycle. The terms fuel pump relay and fuel pump relay switch are used interchangeably. The fuel pump relay begins its job when the automobile operator turns to the ignition on, but before the motor is actually running. At that point, the fuel pump relay in some cars sends a signal to the ignition switch, which in turn sends a signal to the fuel pump to turn on. Others fuel pump relays have actual circuitry inside of them that receive the ignition signal and directly signal the fuel pump to engage.

Have a great day!

Underneath your hood, behind the passenger side headlight, behind the core support, is a bank of 2-8 relays. One of those relays is the relay needed for your fuel pump. There will also be a fuel pump relay fuse located there. The relay designation should be on the cover of the relay compartment.