The fuse F4 as provided in the wiring diagram (Thank you for the diagram)
This fuse is blowing when turning the key to start the car even with the starter disconnected. when the key is in the run position it does not.
The wires from the ignition are R lg and G rd they both are connected together in the plug under the dash with one plug from the stering column. The other ends go to the starter solinod (R lg) and the Voltage regulator (G rd). I replaced both the starter solinod and the voltage regulator. Additional note even with the fuse blown the starter solinoid will activate providing voltage to the starter. What else should I be investigating?
What happens when you try to start it with the R wire to starter solenoid and G wire to voltage regulator both unplugged? If it still blows the fuse, it seems to me it’s most likely a bad ignition switch that is intermittently shorting the start voltage to ground.
Edit - just realized F4 is a different voltage source than the start voltage to the solenoid. Yeah, that sounds like a bad ignition switch.
I will test with both unpluged together and separately. I will provide the results tonight.
I am restoring the car from a rough state. The last owner changed the distributor from points to a pertronics hei and it ran about a year ago.
thank you.
We need to know which diagram you are using. The dealer service diagram has a different #4 fuse than the owner’s manual and is likely different from others as well.
Below is the diagram from the 73 Cougar dealer’s diagram, is that the one you are working with? If so, #4 is for the courtesy lights and clock, which is constant power regardless of the key position. If it’s blowing in Start, then you have something wired incorrectly that is causing an excessive draw or grounding the circuit.
Here’s the link to a free download of the 73 diagrams from WCCC
This is going to help you a lot.
Thank you all for your help with this.
The diagram you provided is different than the one in the scamatic I downloaded.
The fuse is F6 in the diagram right next to the heater (14v) you provided. The wire connector that is shorting is the Red G that is attached or in the same socket plug position with the Green R.
This appears to go to both the ingntion switch and the nuteral safety switch. In the scamatic I downloaded it shows this wire as Red B. I am still tracing the Red G to see where it goes. The nuteral safety switch is working as no power goes to the Green R wire when it’s not in park or nutural. And thanks for the light bulb trick.
I finally received the ignition switch and that did the trick. The fuse isn’t blowing when starting or in the on position.
thank you.
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