I literally just replaced my starter with a brand new Napa gear reduction starter.

Now the truck won't start via the key. The problem (if there is one) is in the key circuit, not the starter. I am able to jump the starter solenoid from the battery and it works as its intended to.

First off, I've bypassed the fender solenoid. It quit working some time ago and a bit redundant if you ask me, so I took the key/start wire and ran it directly to the solenoid on the starter. I ran the truck this way with the factory starter for some time without a hitch so why Im suddenly having a problem is baffling me.

After doing some diagnosis work, I'm showing 6 volts on the key wire that activates the fender solenoid, when cranking. Did Ford use a resistance wire in the circuit??? Or is my key switch likely bad?

If I try cranking it with the key, it will randomly work.

If the key switch is "bad" I'm thinking maybe the old starter solenoid didn't mind the lower voltage. The Napa solenoid seems to want a full 12 volts. Why the key isn't producing 12volts to me is either because sonething upstream is stopping the full voltage from getting thru or it's designed that way.

Any help is much appreciated!

 

More than likely you have burned the contacts in the ignition switch. Ford put the starter relay on there for a reason, to take the load instead of the switch.

 

<p>yup, sounds like you smoked the ignition switch. the starter pulls too much power for the ignition switch to handle, that is the reason for the fender mount starter relay.</p>

 

Huh, I would have thought the switch could handle the lower current draw of the solenoid but the starter solenoid might be too much. I have a suspicion that the old starter wasn't affected by the 6 volts. The new starter wants a full 12.

Regardless I grabbed a new switch and fender mounted solenoid and will try again tonight.

Any thoughts on if the neutral/safety switch could be bad as well or in place?

 

My F350 was wired the way you have yours when I got it, which I discovered after it started cranking intermittently, and I assumed starter, but I put the wiring back to stock and made no other changes, and it works just fine again.

 

<p>NSS will either work or not. it will not cut voltage when bad. that is a low current circuit.</p>

 

It's not a low current circuit in this case, being miswired as it is now. Pulling the current draw of the solenoid through the switched wiring could have taken out the ignition switch, the neutral safety contacts of the TRS (if so equipped), or the start contacts of the clutch switch (if so equipped).

The OP's profile _suggests_ that it's a manual, so that switch on the pushrod would definitely be worth checking.