QuestionDick,
I have a 1966 Mustang 2+2. It won't start with the key. I can jump from bat to "s" on solenoid, starts fine (key on). Jump from bat to "i" on solenoid key on, no joy. New solenoid. Ran new wire to ig switch from "i" solenoid, no change, except lot more voltage to "i" post vice before (10 v to 5.5 v). Back-up lights come on when I turn the key on, stay on after start. These are routed through neutral safety switch, I'm thinking the car "thinks" it's in reverse so won't start and I need to correct/re-adjust neutral safety switch. Your thoughts?
Thanks.
tim
Answer Don't connect from the Battery to the "I" terminal on the solenoid - that terminal is connected to the ignition coil and you will overheat the coil and burn out the points if you put 12 volts on it. It is used to bypass the ballast resistor only during cranking - it is not involved in making the starter turn.
I think you have diagnosed the starting problem correctly - all Ford products of the 60s and 70s have a problem with the neutral safety switch - they often wear or otherwise go out of adjustment, but usually, if your car has column shift, you can make the car start by wiggling the shift lever while you hold the key in the "Start" position. Since the backup lights are coming on, you will probably find that the shift linkage is worn and sloppy, or the switch has shifted on it's mounting bracket.
If this is the case with your car, you can perhaps improve the situation by moving the neutral safety switch in it's mounting a small amount, but most likely you are going to have to replace it. By all means, find it and move it around a small amount first - but don't be too surprised if that doesn't fix it. Of course, all the wires in the circuit from the ignition switch to the "S" terminal on the solenoid should be inspected also - as a loose or broken wire would cause a failure to start, except that wiggling the shift lever wouldn't have any effect on it. Since putting it in "Park" makes the switch think it is in "reverse", maybe if you pull the shift lever slowly down toward the "Reverse" position, the switch will think it is in Neutral, and allow the car to start.
None of this is rocket science - you'll just have to examine the shift linkage and switch mounting to find exactly what has worn or moved out of position.
Good Luck
Dick
