2002 F150XLT, 4.2 V6, 2wd, 5 speed manual, 96,000 miles


Yesterday afternoon, with no warning, it just doesn't crank. It cranked, started and drove fine until I came out of the grocery store, then no crank. Everything acts normal when I turn it on - the seat belt chime sounds, idiot lights come on momentarily, fuel pump hums, etc., just nothing when I turn the key to the start position - not so much as a click.


I can hook a remote starter to the starter relay, and it cranks, starts and runs normally with the key in the on position. Battery strength seems normal, but it is getting weak since I've been messing with it trying to figure out what's wrong.


I've looked through the fuses in both boxes, and none are blown. I have NOT tested any of the relays in the boxes; I don't know which one it might be, and the list in the owner's manual doesn't label any as being for the start circuit. There is one fuse with "start circuit" in the name; I tested it for continuity and it's good; I tested the blades in its socket and I'm getting 12V between them.


I bypassed the clutch pedal safety switch - no change. I opened the clutch pedal switch - it's in pristine condition. I tested the switch with a multimeter - the starter circuit closes when the slider goes all the way forward.


I had an assistant step on the clutch and try to start it while I put a multimeter on the wire that goes to the starter relay. I got a strange voltage reading (less than 12, I think, but the scale on my multimeter is confusing) when he pressed the clutch down, but there was nothing else when he tried to crank it. These was no reading when he tried to crank it without the clutch pedal pressed (which is normal).


I'm stumped. What else is there to check? Bad ignition switch? A relay I'm missing? Thanks.

 

The starter circuit is pretty simple on a manual.

Ignition switch > F21 > CPP switch > Starter relay on the firewall.

Check for F21 to go HOT in START first, that will tell you if the ignition switch is working or not. Once you know that, it's pretty easy to diagnose the rest of the circuit by successive half-splitting without taking the whole thing apart and testing each individual part.

You can get readings on fuses without removing them from their socket. If you look on the "back" side of the fuse, you can see holes in the plastic housing that provide access to the metal contact pins.

 

OK, F21 tested as advised - does not go hot when in start. I did see the test points on the fuses, too - never noticed those before.

Can I conclude from this that the ignition switch is bad? If so, I presume I can drive the truck this week using the remote starter, without damaging anything.

 

Assuming there is nothing else notably wrong with the operation of the other systems on the truck, I'd conclude it's either the ignition switch or the wiring between the switch and F21. It would be prudent to check the WHITE/PINK wire on the ignition switch connector to see whether or not the switch is putting out the power when turned to START.

No harm will be caused by using the remote starter switch as long as you are absolutely safe with regards to starting the engine ONLY in neutral as the clutch interlock is being bypassed when you use the remote switch.

 

When I dropped the ignition switch, I found a wire completely separated at a butt connector about 2" from the switch. I put a picture in the gallery. There's a red wire coming out of the switch plug, then a butt connector, then a short (2") black wire that ends in a stripped and flattened bunch of strands, then a butt connector with an empty end, continuing into a red wire. Presumably the black wire just pulled clean out of the connector. Is this (the short piece of black wire and butt connectors) normal, or is it a repair? I'm the original owner, and I've never been in here before.