Hello all
I am newer to these older diesels but picked up a '91 7.3l F250 and found this forum useful in figuring out some of the issues plaguing it. I am currently stuck on one problem and would appreciate help troubleshooting - searched without luck so I decided to stop creeping around and sign up so I could ask directly.

Right now glowplug warm up times are good, I can hear them clicking (also clicking sounds good/proper timing there), all my dash/aux power is good, but the engine won't crank. I tried jumping the solenoid, which worked, so I replaced the solenoid: same problem. Put a voltmeter on the wire going to the solenoid from the ignition: nothing when trying to start. After some searching it seemed like the clutch switches had a reputation for going out, so I tried jumping that with the same results - no start. I don't think the problem is in the ignition because all the aux power works, but was hoping for some guidance chasing this issue down.

The truck was starting fine before this happened, the only other strange thing I noticed (possible total coincidence but perhaps related) was that the last time I drove it without needing to roll start or jump the solenoid, at one point I jumped on the gas coming off a light and the passenger's side headlight went out. Still trying to fix the starting issue before addressing that problem, but since then I've had this starting problem and was wondering if I could have shaken something loose that caused one (or multiple) connections to break and the headlight was another indication of this. Just speculating here.

Any help would be appreciated, and if you know the color of wires you're referencing that would be really helpful as well! Thanks in advance

 

Was the key getting hard to turn before the no start? If it was there is a pot metal wishbone shaped piece that connects to the actual switch that will break. Remove the cover from the column that is between the steering wheel and the dash. There will be a small rod that trns along the top of the column that connects the wishbone pice to the actual switch. Turn the key to see if that rod moves.I don't recall which way the rod moves, but move it the same way as it does when you try to start it. If the starter engauges that wishbone is probably broken. Also, the actual switch is located on top of the steering column under the dash that can go bad, or get out of adjustment.

 

Bingo.

The rod moves but evidently not far enough - I tried pushing on it in a little bit farther while turning the key and it fired right up. Now I guess I rip apart the steering column and replace either the wishbone or readjust the switch.

Thanks farmert.