checking for grounds in electrical system

[bink220]

Hello, I have a 1966 Belvedere and i replaced the engine bay and headlight harness with new. I have the negative side of the battery hooked up and the positive lead is unhooked. I'm using a test light between the positive post of the battery and connecting the test light to the positive battery lead. The tail light harness is already installed but I did not hook up the headlight harness yet. All fuses are in and the test light did not light. I'm thinking that is a good thing?
Now when I turn the key on the test light, lights. I removed one fuse at a time and the test light lights, I removed all the fuses, left the key on and the test light is still lite. Is this normal? Or is something wrong? Thanks for any suggestions or help. Rick

 

[Canadian1968]

It sounds like the vehicle is only partially wired, so its hard to say what you are doing here .

But your test lead is simply completing the circuit. You turn the key on and it energizes the ignition / run circuit in the car. Pulling all the fuses does not stop all the power flow threw the car.

I don't think there is anything wrong from what you are saying

 

[bink220]

That's true, I have the head light harness to wire in yet. Thanks and that does make scenes to me now about the starting circuit. Thank you for the help!

 

[dvw]

The test light should not light. If it does you have a complete circuit with the controlling device (switch, key) in the off position. I use this as a quick method to test for key off draws.
Doug

 

[Canadian1968]

The test light should not light. If it does you have a complete circuit with the controlling device (switch, key) in the off position. I use this as a quick method to test for key off draws.
Doug

He said the light only comes on when the key is turned on.

 

[bink220]

The test light should not light. If it does you have a complete circuit with the controlling device (switch, key) in the off position. I use this as a quick method to test for key off draws.
Doug

With the key off the light does not light. I created a direct short in the tail lights, the test light lights. I have to agree what Canadian 1968 mentioned, the starting circuit is separate from the rest of the wiring circuits, Correct me if I'm wrong. Rick

 

[Shorthorse]

I may be a bit confused but you said you are checking for grounds, you have the positive battery post disconnected, the negative battery post connected and you are connecting the test light to the positive battery post. If I have this wrong, disregard the rest of this.
If I read it correctly, your light should light anywhere you touch the probe to a ground. The ignition switch is irrelevant. The probe should not light on any positive connection.
Big however,,, when checking light circuits for ground, you must remove the bulbs. A bulb element is nothing but a high resistance short to ground. Depending on the sensitivity or your test light, it may light on the positive side including the fuses by reading the ground through the bulb elements. This is true of any device with some resistance to ground. It might be better to us a volt/ohm meter set on ohms. It makes it easier to tell between a dead short to ground and a high resistance to ground.

 

[bink220]

I may be a bit confused but you said you are checking for grounds, you have the positive battery post disconnected, the negative battery post connected and you are connecting the test light to the positive battery post. If I have this wrong, disregard the rest of this.
If I read it correctly, your light should light anywhere you touch the probe to a ground. The ignition switch is irrelevant. The probe should not light on any positive connection.
Big however,,, when checking light circuits for ground, you must remove the bulbs. A bulb element is nothing but a high resistance short to ground. Depending on the sensitivity or your test light, it may light on the positive side including the fuses by reading the ground through the bulb elements. This is true of any device with some resistance to ground. It might be better to us a volt/ohm meter set on ohms. It makes it easier to tell between a dead short to ground and a high resistance to ground.[/

Yes i have the negative lead hooked to the battery, the positive lead is disconnected. I'm using the test light between the positive post on the battery and the other end to the disconnected positive battery cable. With that said the test light does not light, i created a ground by placing a jumper from the tail light to the car body, the test light lights, when I remove the temporary ground the test light goes out. That tells me there are no grounds in the car body wiring or any power going through the fuse block. When I turn the key on the test light lights, referring to what Canadian 1968 mentioned the start circuit is entirely separate from the power going through the fuse block... My main concern, i really don't the car to catch fire... thanks for your input. Bink