ignition wire on starter solenoid

[jtassin]

This is Jimmy t again.

2 weeks ago, try to start my 72 mustang for a ride.  Sounded terrible like the starter was engaged even after the engine started.  Try to turn the ignition off, key would turn , but would not turn engine off. finally killed.   By then battery was dead.  On Saturday, I tried to jump it.  But as soon as I connected the battery, the engine tried to turn over.  After checking some of the comments, I figured it may be the ignition switch.  As per the info, I was told I could verify that by disconnecting the ignition wire to the solenoid and try to jump it again.  It was described as the small wire.  Well, I am confused with that description.  If someone can post a picture and point me to the right wire, I would be greatly appreciative.

Thanks

Jimmy t

 

[Hemikiller]

Starter solenoid has four connections

Battery (+) - the large post in the front

Solenoid (S) - which activates the solenoid to engage the starter, controlled by 12V from the ignition switch.

Ignition (I) - this is the booster circuit for the coil. When the solenoid is energized by the (S) terminal, it backfeeds 12V to the coil for faster starting with points.

Starter (+) - the large post in the rear

If the starter solenoid fails, one mode is that it sticks in the energized position, where it constantly provides power to the starter regardless of where the key is. If you remove the wire from the small (S) terminal, and it still cranks by itself, then you have a bad solenoid. If you remove the wire from the (S) terminal and it stops cranking, it could be a bad ignition switch, or you have the (S) and (I) wires reversed. 

By your description, I'm going to say you have a bad solenoid. I highly recommend a top quality replacement from Motorcraft, part # SW7663

https://www.rockauto.com/en/moreinfo.php?pk=6586492&jsn=3

 

[jtassin]

Hemikiller:

When I disconnected the ignition wire from the solenoid, nothing happen.  When I connected the ignition wire back; wire started smoking all around the solenoid up to the alternator.  Hurry up and disconnected.  Do you think that I should change the solenoid also with the ignition switch?  When you say ignition switch, are you talking about the cylinder or the ignition switch assembly?

Thanks,

Jimmy t.

 

[jtassin]

Hemikiller:

Just wanted to say thanks for your help.  Changed the solenoid and a new battery.   Solved the problem.  Thanks for all your help.

Jimmy t.