Wiring question

[John P.]

I am in the middle of an investigation of a no-start problem with my 1965 L79 convertible.

when I turn key on I have radio headlights etc. meter shows 12.9 v at horn relay etc. turn key to start:no sound, ammeter spikes to extreme left

is there a fuse in the harness involving the purple wire from ignition switch to the solenoid? Diagrams suggest there may be.
Any thoughts on where issue might be?

[Richard M.]

Re: Wiring question

John, Is yours manual or automatic transmission?

The diagram shows a plug at the purple circuit for Powerglide neutral safety switch. It's not a fuse. Manual trans usage simply wire the 2 plugs together. Located above the wiper motor in the engine harness.

You may have a short in the purple wire down by the starter, or a shorted solenoid or shorted starter. Remove the purple at the solenoid and test the wire circuit again. If ok, something in the starter is likely the fault.

If PG, your neutral switch may be shorted to ground somehow.

Rich

[John P.]

[Frank D.]

Re: Wiring question

I have had dead/weak cells in a battery cause that condition...
Put a voltmeter across the battery terminals and crank the car, if the reading
is much below 9.5V then the battery is worth investigating...

Autozone, etc. will load test a battery for free, but if the car won't start you'll have to remove it.

There is also the classic failure where the copper contact inside the starter solenoid is burnt or not making contact:
https://www.youtube.com/watch?v=tYrZmwEmmis I don't recall if this condition would cause the ammeter to peg
negative - prob not.


One other thing is to put the car in gear on a flat surface with the parking brake off and "rock" it a bit..
Then put the car in neutral, parking brake on and try cranking it.

The wife is already serving New Year's Eve coffee and Kahlua so the above suggestions may or may not be relevant...

[Donald O.]

Re: Wiring question

AutoZone,etc, will also test/check the starter but you would have to bring the starter in to them - they do it for free.

Don

[Domenic T.]

Re: Wiring question

A meter to the left indicates a power wire or starter problem.
I have seen the wires going to the solonoid burnt from the exhaust. The starter usually tells you something is going wrong before it go's to a problem.

You can test the starter by jumping the terminal on the solonoid to the terminal going from it to the starter. That can be a danger if car is in gear.
Also I would (if you test that way), hook up jumpers and get out from under and simply touch the hooked up jumper and it should run the starter only. If so, then disconnect the purple from the solonoid and see if the meter does the same.
If it does the same then it's the start circuit to the solonoid. If it dosent go to the left then it's at the starter.

Dom

[Danny P.]

Re: Wiring question

I am in the middle of an investigation of a no-start problem with my 1965 L79 convertible.

when I turn key on I have radio headlights etc. meter shows 12.9 v at horn relay etc. turn key to start:no sound, ammeter spikes to extreme left

is there a fuse in the harness involving the purple wire from ignition switch to the solenoid? Diagrams suggest there may be.
Any thoughts on where issue might be?

Put a 12v test light on the purple wire at the starter get someone to turn the key over if lights up its the starter if not broken purple wire somewhere or even bad ignition switch.