How do I trace a wire back to source?

marks737

marks737

Active Member
Sep 15, 2009
333
NJ
Boat Info
2005 390 Sundancer
Engines
Cummins QSB 5.9
My glomex amplifier light doesn't come on when I turn the knob. Checked the fuse and it's good. How do I find the other end of the wires where they connect to 12V. Source. I don't think there's power to the amp.
 
I've found that a network toner/tracer is a pretty handy rig for chasing down end-to-end wiring of any kind....boat, home, etc.
You see them on ebay for 20-30 bones (and way up!), and I'm fairly sure I've seen them in the elecrical aisle of the home improvement stores.
 
Well I checked the wires for DC today. I'm getting power to the amp. So it must be bad. Sent it to IMTRA today for replacement under warranty.
 
marks737 said:
Well I checked the wires for DC today. I'm getting power to the amp. So it must be bad. Sent it to IMTRA today for replacement under warranty.
Click to expand...

Let us know how it turns out.
 
In answer to your original question.....in case you ever want to do it sometime in the future......use a multimeter to check for continuity.

Turn power off everywhere to avoid the risk of shorting something out.

One meter probe on the end of the wire in question that you're searching for the other end of....other probe to touch all other wires and watch for continuity.

If you're starting with a black wire....then start with touching every other black wire you can find. Hopefully.....as happens so often......no one will have been messing with the wiring and changed colors on you. I find that happens very often and is a real pain sometimes when hunting for wires. In a perfect world....all of the original color coding would still be in tact.

If need be......because the one end is too far away from where you're searching for the other end........splice on another long piece of wire long enough to reach the area where you're searching for the other end.

Never used one of those toner/tracer things but it sounds like a handy rig. I'm still an "old school" kinda guy with a multimeter. :grin:
 
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Tone generators are a good thing, but they do have their place. If there is no 12 volts at the amplifier, disconnect & isolate the wires from the amplifier and clip on the tone generator to the + & - wires. Now take the probe and follow the wire + wire back until you lose the signal and you will have found the source of your problem. Before starting this procedure, measure from + at the amplifier to - and you should get 12 volts. If no voltage, measure from + to a known dc ground & you should get 12 volts on your multi meter. If no voltage, connect to - at the amplifier and measure to a known 12 volts + source. What you are doing here is trying to determine whether either your power source or ground is good.
 
Old Vet said:
In answer to your original question.....in case you ever want to do it sometime in the future......use a multimeter to check for continuity.

Turn power off everywhere to avoid the risk of shorting something out.

One meter probe on the end of the wire in question that you're searching for the other end of....other probe to touch all other wires and watch for continuity.

If you're starting with a black wire....then start with touching every other black wire you can find. Hopefully.....as happens so often......no one will have been messing with the wiring and changed colors on you. I find that happens very often and is a real pain sometimes when hunting for wires. In a perfect world....all of the original color coding would still be in tact.

If need be......because the one end is too far away from where you're searching for the other end........splice on another long piece of wire long enough to reach the area where you're searching for the other end.

Never used one of those toner/tracer things but it sounds like a handy rig. I'm still an "old school" kinda guy with a multimeter. :grin:
Click to expand...

That is of course until the one time your looking for a wire (because of a problem) and the "problem" ends up being a bad/shorted/cut/corroded wire and you have no continuity!

With a tone tester you can actually set it up so that you use the wand and literally follow the wire from your known source. You can also find bad wires and where they are broken. Can't do that with a meter.
 
Thanks guys. I checked the power to the amp. and it was fine. So I sent the amp. back to IMTRA, they found silicone inside the fuse holder, which blocked the connection. They cleaned it up and it works fine, they're sending it back to me.
 
I do a little trick with a multimeter in my class. Touch the + to the positive terminal on the battery then touch the - to any rubber hose on the cooling system. I can get 24V through the meter touching the - to many rubber parts including a rubber protective cover on a wheel loader. This would lead you to believe you were getting a good ground or full 24v when you are actually only getting ghost voltage through the meter with no amp load.

A tone tester is the way to go.
 
"That is of course until the one time your looking for a wire (because of a problem) and the "problem" ends up being a bad/shorted/cut/corroded wire and you have no continuity!"

Ummmmm....yup....good point. :thumbsup:

Must look for one of those tone testers to add to my tool collection.
 
Old Vet said:
Hmmm....well...for what they're worth....the 2 reviews for that thing aren't great. Maybe I'll hunt for a better one. "shrug"
Click to expand...


A decent unit will go for around $100 +
 
Sous- That's a nice looking piece of equipment. I wish I felt more knowlegable about using it. Does it come with instructions that a non-electrical guy can figure out?
If I understand its use, you'd think it would come with a set of really long lead wires to (altho I guess you can just use wires)
 
Paladin said:
Sous- That's a nice looking piece of equipment. I wish I felt more knowlegable about using it. Does it come with instructions that a non-electrical guy can figure out?
If I understand its use, you'd think it would come with a set of really long lead wires to (altho I guess you can just use wires)
Click to expand...

Yea there are instructions but for the most part its pretty simple.

The square box is the part that induces the tone into the wires. It also has a simple continuity light as well. It is designed for electrical circuit testing so longer leads isn't really necessary, as you will typically be picking up the wires you want search for at one known location, like the buzzer that won't buzz.

So you simply clip the leads to the wires you want to trace, flip the switch and then use the "wand" to start following. There is two general methods for this. If all your wires go back to a single spot, like a distribution panel, you can just use the wand there and see which one has tone. In this method (assuming the wire isn't shorted or broken), you will likely hear tone all over the place, but as you touch the tip to each individual wire you will know which one it is because your tone will go from beep, beep, beep to BEEP, BEEP, BEEP.

The other method which is useful if you've got a bad wire or if your wires go multiple places is to start at your known location where you attached the generator and then use the wand to start to follow the wire... in other words start to drag the wand across the walls/floor/ceiling/ whatever and you can hear the tone as you go along if it stops you found the bad spot or the spot where the wire turns direction.

Here is a decent video on how to use it in the first method: http://www.youtube.com/watch?v=jP0AtN9hTP4
 
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