Out of nowhere my 71 F250 would not start. Troubleshooting I crossed the solenoid to the battery with a screwdriver (with the key in the on position of course) and it fired right up. I went ahead and bypassed the ignition with a remote push-button started switch. It works fine and starts up every time but it was supposed to be a quick fix until I secured another ignition tumbler. I found the tumbler with key (OEM salvaged from a parts truck) on Ebay with an assurance that it worked when pulled. I installed it today and.....NO DICE. Silence...The push button starter still worked with the key in the on position. So was this tumbler just bad like the one I took out? Or am I missing something? What else could it be? Suggestions? I really want to get rid of the push button ignition and return to a normal key-in-the-ignition start up.

Thanks in advance for any help.

G

 

look at the ignition switch electrical connector and the ignition switch . look for burnt connections. auto supply stores should have wiring pigtails & switches, also ck ebay & internet auto parts

 

1967/72 F100/750 ignition switch cylinder w/key is the same.

But, there are THREE different 1967/72 ignition switches!

1) 1967 F100/750 switch is 1967 only. It was also used on 1965/67 Galaxie/LTD (C5AZ-11572-A).

2) 1968/69 & 1970 F100/750 before serial number G90,001 switch (C8AZ-11572-A) was defective, shorted out and caught fire!

Ford replaced it with an ignition switch kit (D1AZ-11572-C) that included a pigtailed wire harness/plug that had to be spliced into the dash harness.

3) 1970 from serial number G90,001 & 1971/72 F100/750 used a different switch (D0TZ-11572-A).

 

The tumbler does not usually have anything to do with the electrical function of the switch. Other than of course to allow you to turn the switch into the various positions.
So if your switch is still turning with the key, with both the new and old tumber/cylinder, that's not the issue.

But for clarity, are you saying you're not able to crank the starter with the key? Or it will crank and just not start? Two different functions of the ignition switch.
If it's not cranking the starter, do you have an automatic transmission? If so, you may need to check the neutral-safety switch.
The three things that are most common points of failure (in order of their appearance sometimes) are:

1. Neutral Safety Switch (either out of adjustment or full failure)
2. Ignition switch (not sending a signal to the Red w/blue wire)
3. The wiring in-between both.

On some trucks with manual transmissions, but I'm not sure when this may or may not have been used, there may be the same NSS wiring harness, but instead of a switch on the steering column there is a simple jumper loop of wire to connect the two halves of the Red w/blue wire.
Obviously since your starter relay/solenoid works fine with you manually starting it, the Red w/blue wire on the small "S" terminal is not getting power when you turn the key. You just need to find out where the power is being stopped.

Does your truck have an auto or a manual transmission?

Paul

 

Is there any wiring at battery or anywhere on any OEM wiring that has FUSEable Link on the end of any wires?
manual transmission may have a neutral position switch that goes bad and will not pass electrical connections.
Good Grounds are needed sheet metal to frame, frame to engine, Battery to frame/engine. BAD GROUNDS cause problems.
Some trucks Have a switch activation upon depressing the clutch pedal in order to start the engine.
AutoTrans have a switch on the steering coloum that activates starter as mentioned earlier in other posts.
chech the Fire wall bulkhead electrical Wiring Harness connection to ensure there is good connections.
use a test light to check +power going in to switch, check the terminals coming out of switch for power out to the solinoid wire. check along solonoid wire for power or no power.
Its hard to troubleshoot without knowing what all has been checked.
13mm

 

First off thanks !

Motor does not crank at all when I turn the key, total silence...

I do have an Automatic Transmission...

I switched out the Neutral Safety Switch yesterday. No change...

G

 

Wow thanks...

Auto Trans.. I switched out the Neutral Safety Switch yesterday but still no luck...

Great advice though.

I'll keep you posted...

 

You have to get a test light or volt meter and trace the circuit. Anything less than that is guessing.

 

2X MPH. Also 2X noted above look at the back of the ignition switch and the wiring plugged on to it. Look for clues for what the problem is. Then use test equipment to nail it down.