My 1974 F100 will not start-or crank!
 

I tested the battery it has 12.8 volts . At the same time I was checking the battery's voltage I noticed the wires were backwards on the starter solenoid ! I ran the truck earlyer today and it has been hooked up incorrectly since I owned the truck and I just noticed it now !
So I switched out the solenoid and corrected the wires ( everything worked before which is very strange).
Now the truck is'nt quite dead but the starter will not crank therefore the engine will not start !
I have a automatic and in order to get it to start before I had to play with the slide on the neutral safety switch to get it to crank/start.
I have no idea what is wrong with the truck !
IF I turn the key on the heater works the head lights and everything else -but the starter will not crank .
All of the fuses are in good condtion ( not blown)
How can I determine what is wrong the with out going and dumping a lot of moeny in it ?
IF I try and jump it from the "S" terminal and it starts what does that mean ?
ALso How can I "get rid" of the stupid neutral safety switch?
What do I have to wire in order to make it not safe:D
I have 4 wires on the safety switch but in the connector that the switch plugs into there are 5 wires!
Any help would be great!
sorry for the long post - I did a search and found some info!~

My 1974 F100 will not start-or crank!
 

The neutral start switch may be out of adjustment.

Try putting the trans in Neutral & then park.
Keep trying it.

Have you had the trans in park & touched 12 V to the S terminal?

What happened?

It should get the starter to crank.

What colour are the wires going to the I & S terminals?

My 1974 F100 will not start-or crank!
 

I took the safety switch right out of the truck.
It doesnt have a column shift anymore - it now has a floor shift !
The colors on the "s" is RED+BLUE "I" is BROWN.
I haven't tried running 12 volts to the s terminal it is dark out and its late:( - I bet it starts though - I am usually pretty good with this kind of stuff - but I am stumped - The truck ran earlier today!

My 1974 F100 will not start-or crank!
 

Red/Blue wire shoud go to the S Terminal.

My 1974 F100 will not start-or crank!
 

Ok - the red and blue is on the "s" - what do you think?

My 1974 F100 will not start-or crank!
 

With the trans in Park,
Take a wire and run it form the +post of the battery to the S terminal and see if the starter cranks.

If you had 2 more hands you could put a multi-meter to the
I terminal to see if there was 12 V when the starter cranks.

My 1974 F100 will not start-or crank!
 

With the neutral safety switch out of the truck you'll have to jumper the two wires that connect through the switch when the switch is in park or neutral. You'll have to be careful 'cuz it'll start in gear that way. Not sure why there would be 5 wires tho'. 2 should be for the starter and 2 should be for the back-up lights.

My 1974 F100 will not start-or crank!
 

That red/blue color wire should follow through from the ignition switch, through the neutral start all the way to the starter relay. You should be able to find two red/blue wires going to the neutral start switch. Cut these and twist them together. This will by-pass the neutral switch.

My 1974 F100 will not start-or crank!
 

Alright I think the starter solenoid is bad .
I disconnected the igniton wires from the ignition and the neutral safety switch - when the positive lead is connected to the battery the engine will crank over and attempt to start except the starter will not disengage .
Like I said I think it is the solenoid
What do you guys think?

My 1974 F100 will not start-or crank!
 

https://www.ford-trucks.com/user_gal...oid=16899&.jpg

If you jumped point #3 or point #1 to to point #5 (which should be the "s" terminal), with nothing else connected to #5 except the jumper, then yes, it sounds like the contacts in the relay are bad and welding themselves together occasionally.

My 1974 F100 will not start-or crank!
 

Thamks for the responces ! I did some more testing and came to the concluesion that it was the solenoid - so I replaced it and the solved the problem!