Inertia switch keeps cutting off while cranking engine

post a problem first, not a hunt for things not there.
let me guess engine cranks but does not start and run and stay running , right <must we beg?
is fuel pressure zero 0- or too low , not even measured/?
no starts short list of huge.
1: fuses blown. we test those first.
2; bad fuel. (old or diesel over gasoline put in).
3: pump is dead or FPR bad and fuel pressure crazy too low.
4: no spark the PCM cuts fuel if SPARK fails by law, so does. if did.
5: scan tool shows DTC errors you ignore, even cranked?
CRASH CONTROL MODULE , DETECTED CUTS FUEL INERTIA SWITCH.? what the logic does here, I have no clue, ask a German?
6: ANTI-THEFT SYSTEM LAMP SHOWS noT HAPPY/?

There are several answers depending on whether the engine cranks or not. If it does not crank, check the brake pedal safety switch on the pedal lever. There is an inertia switch which may be in the trunk on your model and this will cut off the power to the fuel pump. Newer year models have the inertia switch by the front kickpanel. In either case a push button on it will restore power.

That being said, if you use a little starting fluid and the engine tries to run, you know it has a fuel shortage problem.

Your best bet , take it to a qualified repair shop .

If you don't hear the pump running, it's likely not the fuel filter. However, you'll need to determine if the pump is getting power when it will not start. There should be a fuel pump inertia switch identified in the owner's manual. It's likely near the passenger side kick panel inside the truck. This is typically a convenient place to check for voltage from the fuel pump relay to make sure voltage is getting to and through the switch. There have been a fair number of folks that have had issues with the inertia switch failing. If you have voltage through the switch for about a second after the ignition switch is first turned to the Run or Start position, then you need to find out if the power is making it to the fuel pump. If there is no voltage to the inertia switch immediately after they key is turned to Run/Start, then you need to work towards the battery.

-Rod

Have you checked the "Bump Switch" this is a small inertia switch which turns offf the fuel pump to prevent it running in the event of an accident. They are usually mounted in the boot(trunk/load area) . There should also be one mounted under the front of the vehicle to initiate the Airbags. They usually cut the earh return(at least it does on my Granada, XR3i and Sierra XR4x4) hope this helps.

red button reset for fuel pump if u rool over it cut off fuel...spray with staring fluid to see if it fires

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

Did you tape a fuel pressure gauge to the windshield,to see if your really loosing fuel, when it quits.
Did you consider the MAF sensor,TPS Sensor.
The pump won't run if it isn't needed. If the PCM doesn't see a crank signal or other data it needs,it won't keep the pump going.
You may be working on the symptom,not the cause.