How to make a lamp/wiring test probe

[roundthebend]

Related to my other Q regarding Vectra towbar wiring.

I want to make a simple device which will let me check which wire in my car's loom does what function.

So, it'll be a bulb with a wire and clip attached to each pole. If I clip one end to the wire I want to test, and the other to earth, then run a test.....

e.g. my Haynes manual says that the black/yellow wire is for brake lights. So I clip one end of my device to the black/yellow wire, and another to earth. Then, press the brake pedal and my test bulb should glow, right?

OK, so can anyone give advice on how to construct one of these devices simply? Can anyone advise how to clip onto a wire in a loom? At the moment, I'm thinking I'll just use a Scotchlok and then use some insulating tape to repair the sheath.

 

[Stivino]

Get an old indicar lamp, side repeater or something like that and just use as much of it's own wire as you can salvage. Follow the instructions that I gave you for the hron on your other post where I told that an audible tester is better for what you want than a visible one.