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Discussion Starter · #1 ·
Today I figured out that the wiring from my radio somehow connected my alternator to the ignition system. When the key was out the car still ran. I found out today how powerful the spark from the coil really is... 馃ぃ

Anyway I only had two wires running from the radio; A constant hot to the battery, and a wire to a key on power source. The battery wire was hooked up to a positive distribution block and the key on to the spade terminal on the fuse box.

How are those two wires preventing my car from shutting off and since they are how would I go about wiring my radio?

In the photo the radio was connected to the unused space terminal.
 

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Today I figured out that the wiring from my radio somehow connected my alternator to the ignition system. When the key was out the car still ran. I found out today how powerful the spark from the coil really is... 馃ぃ

Anyway I only had two wires running from the radio; A constant hot to the battery, and a wire to a key on power source. The battery wire was hooked up to a positive distribution block and the key on to the spade terminal on the fuse box.

How are those two wires preventing my car from shutting off and since they are how would I go about wiring my radio?

In the photo the radio was connected to the unused space terminal.
Hello 808Mark,

Are you running the stock factory wire harness and charging system? I'll assume you are for my thoughts below.
I think your problem is your radio constant hot and switched ignition power are connected together whether it's external to the radio or internal to the radio. Obviously with both power feeds connected you'd effectively bypass the ignition switch and everything would remain powered. The alternator output it always connected as close to the battery as possible on these 3rd gen Fords and has nothing to do with your run on.

I assume you're using an aftermarket radio? It sounds like you are not using the original switched radio power wire, just wondering why not as it would be really convenient.

One last note, pulling the HT lead (spark plug wire) off the coil will stall the engine but the ignition key is effectively still on and depending on and depending on what you have left on will drain the battery if not disconnected until you sort out the problem.

Cheers
 

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Discussion Starter · #3 ·
Hello 808Mark,

Are you running the stock factory wire harness and charging system? I'll assume you are for my thoughts below.
I think your problem is your radio constant hot and switched ignition power are connected together whether it's external to the radio or internal to the radio. Obviously with both power feeds connected you'd effectively bypass the ignition switch and everything would remain powered. The alternator output it always connected as close to the battery as possible on these 3rd gen Fords and has nothing to do with your run on.

I assume you're using an aftermarket radio? It sounds like you are not using the original switched radio power wire, just wondering why not as it would be really convenient.

One last note, pulling the HT lead (spark plug wire) off the coil will stall the engine but the ignition key is effectively still on and depending on and depending on what you have left on will drain the battery if not disconnected until you sort out the problem.

Cheers
I should've included that information >< I'm running a one wire alternator. One wire directly to the battery and one wire to the dummy light. The radio is aftermarket. To be honest, i never thought of hooking the aftermarket radio to the factory radio. I need to look into that. It seems like it would solve my problems.

It must be that the ignition hot is connected to the spare spade terminals on the fuse box and that the constant hot and keyed ignition on wire in the radio are connected. Man it really tripped me out. I disconnected the radio wiring and confirmed the problem went away so the battery wont die on me. Thank you again for the help!
 

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Discussion Starter · #4 ·
Hello 808Mark,

Are you running the stock factory wire harness and charging system? I'll assume you are for my thoughts below.
I think your problem is your radio constant hot and switched ignition power are connected together whether it's external to the radio or internal to the radio. Obviously with both power feeds connected you'd effectively bypass the ignition switch and everything would remain powered. The alternator output it always connected as close to the battery as possible on these 3rd gen Fords and has nothing to do with your run on.

I assume you're using an aftermarket radio? It sounds like you are not using the original switched radio power wire, just wondering why not as it would be really convenient.

One last note, pulling the HT lead (spark plug wire) off the coil will stall the engine but the ignition key is effectively still on and depending on and depending on what you have left on will drain the battery if not disconnected until you sort out the problem.

Cheers
I seem to have been juked by my car. I reconnected the radio wiring to troubleshoot it, turned the car on and left the key in the off position. I then disconnected the radio wires and it still ran. I smothered it and tried again, but the next time i disconnected the wire leading to my alternator. When i disconnected the alternator wire the car died. I guess my alternator is sending voltage back through the dummy light and by passing the ignition. I'm just glad i know i'll have to put a diode in the line and call it a day.
 

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When my alternator was first installed I returned home and car would not shut off. Turned out to be the wire on starter solenoid had rotated a little and was touching the relay for my convertible top therefore grounding it out so car couldn't shut down. I put a piece of tape between them so it would never happen again. Maybe check that possibility.
 
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