2001 F250 6.8L won't start with the key. But will start by jumpering across the solenoid.

New battery because old one was not holding a charge and had white corrosion coming from the posts. Battery shows 13.5 V when running so the alternator is charging.

Column shift lever seems tight, truck won't start in Park or Neutral, so I am thinking either NSS or Ignition switch. I will check the alignment of the NSS, but since it doesn't start in either position, I don't think that the alignment is an issue.

If the NSS is bad, will I ever get voltage to the solenoid when the key is in the start position? Is there a way to determine if it is the ignition switch or NSS? I thought about bypassing the NSS,but can't find a wiring diagram for the correct wire colors.

Any help is greatly appreciated.

 

Did you check the fuse in the starter circuit?

 

Yes. Fuses 20 & 21 in the battery junction box under the hood and fuses 20 & 27 under the dash were all good.

 

Did you check that CJB F21 is actually HOT IN START? It's between the ignition switch and the DTR switch on the transmission and is a convenient location for half-splitting the circuit during troubleshooting.

 

Sorry for not updating the thread lately. I was finally able to get with my son and troubleshoot this a little more.

Only 4.5 vdc at fuse 21 when the key is turned. Also, the radio display shuts off and presets are lost whenever the key is turned to the start position. To me it seems like either the ignition switch is bad, or the wire from the ignition switch to the CJB Fuse 21 is grounding out somewhere. Any other thoughts?

 

It seems to me that your battery is dead.

 

If the battery was dead, it wouldn't start when jumping across the solenoid relay.

 

Sounds more like a connection or conductor with excessive resistance, assuming the battery's voltage is not "sagging" under load.

Use conventional voltage drop testing to pinpoint, starting at the battery's terminals.