Intermittent fuel pump

Three wires - the dark green with yellow stripe comes from the fuel pump relay ! When energized the relay sends battery voltage to the inertia switch via the dark green with yellow stripe wire . Inertia switch's don't go bad ! What's the problem ? fuel pump not working ? Test from the relay > Do you know what a relay is and how it works ? Watch this guy's video ! He shows chrysler first then ford . Do you know how to do electrical testing ! It doesn't matter that your inertia swich has three wires . Only two matter ! Fuel Pump Electrical Circuits Description and Operation

The clicking noise at the relay indicates that the relay is bad, or that the wires to the relay and/or connector is bad.

A relay is an electronically activated switch. Inside is a coil. When 12v+ is applied to one end of the coil, and a ground is applied to the other end, the coil gets charged, creating a magnetic field. This magnetic field literally moves a metal lever from position A to position B. One end of the lever is attached to constant battery power. When coil not energized, the lever rests in postion A (which in the case of the fuel pump relay is feeding the battery power to an unused terminal). When the coil is activated, the lever moves to position B (which in this case is a terminal connected to your fuel pump wire). Thus, when the relay is activated, 12v+ is being directed from the battery to the fuel pump.

This fast clicking indicates that the relay coil is not getting a constant voltage or ground supplied to it, thus the lever is moving back and forth between position A and position B, either there is a wiring issue, a connector issue, or an internal issue with the relay.
The relay has 4 wires, black, grey, orange, green with white stripe.
black = ground
orange = battery = 12v+ always
grey = wire out to fuel pump (on some cars this wire is tan with white stripe)
green/white = signal wire from ECM

When key is turned ON, the ECM sends 12v+ out on the green/white wire to the relay for about 2 seconds - this activates the relay coil for 2 seconds, thus running the pump for 2 seconds (priming). When the vehicle is started, the ECM sees a constant ignition signal from the ignition module, and sends a constant 12v+ out on the green/white wire, thus activating the relay coil constantly, and thus running the pump constantly.
When car shut off, no more constant ignition signal, thus ECM stops sending the 12v+ out on the green/white wire.
So, you can kind of test your connector ...
1) remove connector from relay
2) jumper a wire from the slot for the orange wire to the slot for the grey wire - fuel pump should run - wiggle wires to verify at connector
3) probe black wire slot with ohm meter - make sure black wire has constant ground - wiggle wires at connector
test relay ...
1) remove relay from connector
2) rig a ground wire to the tab that had the black wire when in connector
3) apply 12v+ to the tab that had the green/white wire - relay should click once and do this every time you apply the 12v+

That should help you track it down to either a connector problem, a wiring problem, or a relay problem.

I don't believe it has one. I've heard some pretty reliable sources say this safety switch is a Ford-only product. First check the fuel pump fuse. It's fuse #1 in the Power Distribution Center, a 20 amp fuse.

If the fuel pump in the tank is not turning on to put gas up to the engine, you have a problem in the pump circuit or a bad pump.
There's an easy way to determine which it is. You will need a voltmeter or at least a test light.
Find the gas tank electrical connector. It will be near the tank. A wire loom of about 4 wires will likely come from the top of the tank and run down to an electrical connector, probably close to the side frame rails. Pull the connector apart, and on the harness side (or chassis side, not the tank side of connector) identify the dark green with black stripe wire in the connector. This is the power wire to the fuel pump. You need to check if it has voltage on it when the pump is supposed to be running and pumping.
You will need a helper to turn the key to start and crank the engine over while you check for power with the voltmeter or test light. If the voltmeter says battery voltage-right around 12 volts, 11.8 volts or more- or if the test light comes on brightly, then you know the pump has failed (90% certainty) and you need to replace it.
If there is no voltage on the dark green/ black stripe wire with the engine cranking, it is not a pump problem. You will need to consult a wiring diagram to diagnose the fuel pump circuit. I just looked and there is no inertia switch.
Good luck.

Can you hear the fuel pump buzz for about 2 seconds after the key is first turned ON?
If yes, possible plugged filter or weak pump.
If no, locate the fuel pump relay near the brake booster. Should have an orange, tan/white, red, dark green/white and black/white wires. Unplug it and jumper the orange and tan/white wires for a second or two. Does the fule pump run now? If not, bad pump.
If it does run then it could be a bad relay or circuit.

You can usually go by the wire colors. The fuel pump relay wires are pink, gray, black, and green with a white stripe. When troubleshooting a fuel pump that is not coming on, the relay is the best place to figure out why. You can pull the relay out and put a jumper wire from the battery to the terminal with the gray wire. If the pump runs, you know that isn't the problem. Then turn the key on and use a jumper between the terminals with the pink and gray wires. If this turns the pump on, you know the ignition switch is sending power to the relay, and the fuse is good. Pull that jumper out, but leave the key on. Push the relay back into the socket, but put a jumper from a ground point to the terminal with the black wire. If that turns the pump on, the ground wire is bad. If not, the PCM is not turning the relay on. Reasons for that may be a bad wire from the PCM, a passlock issue, or the PCM fuse/power wire.

Your fuel pump is powered by the GREEN fuse link in the fuse link holder. If you have 2 terminals (both WHITE/BLACK wires) at the fuel pump relay that is HOT all the time (even with the key OFF) then this fuse link is OK. There are no other fuses to be concerned with.

There is also a "Fuel Pump Control Unit" located on the left rear quarter panel, behind the "B" pillar. (See Picture)

Good info on the PATS / theft light. Looks to be the PATS / HEC operation is functioning correctly

The Fuel inertia switch only cuts power to the fuel pump, so if tripped, the truck would have a crank no start issue. Do you have a crank no start, or no crank issue.

To reset, just press down on it. To check if the switch is tripped, check for power at the connector to the fuel inertia switch

Engine compartment fuse # 10 ( 20A ) to the fuel pump relay -> Dark Green w/ yellow stripe wire to the fuel inertia switch -> pink w/ black stripe wire to the fuel pump module.
Check the pink w/ black stripe wire to ground with a meter for power, with the key in the run position.

If you turn the key from off to run ( do not start ) you should hear the fuel pump cycle ( hum, then turn off ).

Could be an issue with the fuel pump relay ( my '01 had a crank no start at ~ 35K miles, bad fuel pump relay ). I proved this out ( after a stupid ID10T error in my diagnoses process ) by jumpering the normally open contacts in the fuel pump relay socket, and then installing the trailer tow reverse circuit relay into the fuel pump relay socket ( same full size Ford Relay ).

Jumpering the fuel pump relay in the relay socket ( remove relay and use jumper wire ), red line


If you have a no crank issue, could be the DTR ( Digital Transmission Range ) sensor on the driver's side of the trans is out of alignment.

Check the start motor relay ( on the firewall on the passenger side ) for power on the Tan w/ Red stripe wire when the key is in the start position ( this is from the ignition switch through the DTR when in park or neutral to the starter motor relay ).

You can test another route, turn the key to the run position, and apply power to the Tan w/ Red stripe wire on the starter motor relay in the engine compartment on the firewall. BE CAREFUL, the motor should turn over, keep clear of moving parts.

Post back a comment to this problem with the results of the testing.

Thanks

white/black stripe - from fuel pump module to fuel pump motor

brown/yellow stripe - same as above

black - fuel pump to ground

green/orange stripe - from fuel pump relay to inertia switch to fuel pump module

4.5 volts , that's not right . Resistance in the circuit . before the relay ! Do voltage drop testing , not ohms . That should stay at vehicle (battery voltage ) It should go low on the other side of the circuit . Watch this video on voltage drop . Voltage is not being pulled low , it should not not drop voltage till it goes through the relay coil , on the ground side .You have high resistance in that green with white stripe wire .

Fuel pump electrical circuit diagnosis no fuel pressure testing GM Mastering Voltage Drop Testing with Pete Meier and Jerry Truglia

HI...
The common cause of the problem that you related.
Is the FUEL PUMP RELAY " Called MAIN RELAY.
Is located : left side under the dash.
Is a BIG relay gray colour. with a connector of 7 or 8 wires.
I recomend replace the relay.

And letme know if you solve your problem.

I hope this information work on your problem.
Thank you for use fixya.