Ign Sw as ground probe

[boschbabe]

In the process of looking for a KEY ON power source in the aftermarket radio harness to tap into for my D+ rerout, all I found was HOT always connections. I know for a fact that the radio turns off with the car, so I was perplexed. I was using the ign keyhole as a ground because it held the probe. Today I used a different ground point and I found a KEY ON source. I tried the keyhole again and that source became hot. Please explain.

[Briano1234]

The ignition switch has constant power, it may not be on with the key out, but when you insert the key, you allow the path of voltage to start.

If you look at the ignition switch there are no grounds on it, only different voltages depending on where the switch is as in off, start, or run.

If you got voltage, when using it as a ground path then you where back feeding it from somewhere.

Always use a Frame ground.

If you are looking for a switched power for your Radio use the black/yellow wire on your defrost switch.

[boschbabe]

I fliggered it out. Inserting something in the keyway turns on the accessory circuit. The aftermarket head unit beeped when I pulled the key out, not when I shut the engine off.