Automotive voltage tester without wire damage?

[pontoon]

Hi all,

I’m looking for an automotive voltage tester that can tell me if I have a hot wire without puncturing the wire insulation.

Bonus points if it can tell me the actual voltage, as I think sometimes the voltage is 5v and sometimes 12v for what vehicles I have.

Thanks

 

[GeoBruin]

Isn't a car's electrical system DC? I don't think Non-contact voltage detectors work on DC wiring. Would love to hear otherwise.

Good luck.

 

[Dumber than lumber]

The Power Probe is the answer.
Multiple versions.
Give me the bonus points?

 

[Wrench97]

The Power Probe is the answer.
Multiple versions.
Give me the bonus points?

Power probes are not inductive pick up they require a direct connection to the wire.

There is nothing that will give a voltage reading on DC circuits without a connection to the wire, the best way is to use a back probe in a connector or by unplugging the connector and very gently front probing making sure not to spread the contacts.

 

[unslow1]

Isn't a car's electrical system DC? I don't think Non-contact voltage detectors work on DC wiring. Would love to hear otherwise.

Good luck.

The only thing on a car I've seen a non-contact voltage detector work for is a firing spark plug wire.

 

[Professional Tool User]

Go look up a wiring diagram. There should be exposed points in the circuit that allow you to check without poking holes in the wiring. If you want to, you can buy inexpensive wire tracing tools like this one.

https://www.princessauto.com/en/auto-circuit-tracer-detector/product/PA0008415002

If you are already invested into a power probe, a wire tracing accessory is available.

https://www.aeswave.com/ECT3000-Circuit-Tracer-p9502.html

But bottom line, I've heard of at least one professional mechanic say that it's just quicker to work your way up the wiring with a test light.

 

[richfinn]

Multimeter and backprobes or the pomona puncturing probe and liquid electrical tape for sealing the hole

You can buy sets of "breakout harnesses" which are manufacturer specific which allow you to tap into the circuit temporarily

 

[Showkey]

Multimeter and backprobes or the pomona puncturing probe and liquid electrical tape for sealing the hole

You can buy sets of "breakout harnesses" which are manufacturer specific which allow you to tap into the circuit temporarily

Not a great idea.......OP by his question already knows that puncturing has a few problems.

Some of those CAN BUS wires are 2.5-5.0 volts, some are also shielding.
Some are twisted pairs.....They look like regular wires. They can be any ware in a modern car.

Puncture one of those and ground that BUS or short the BUS you will multiple problems for years to come. Especially if the open, grounding or shorting is intermittent....like only happens hot or cold days or on Tuesday mornings.

The OEM dealer tech will testify after the car visits the aftermarket tech installs the alarm, remote start or the audio system........they are infamous for “improper punctuation.”

 

[richfinn]

Not a great idea.......OP by his question already knows that puncturing has a few problems.

Some of those CAN BUS wires are 2.5-5.0 volts, some are also shielding.
Some are twisted pairs.....They look like regular wires.

Puncture one of those and ground that BUS or short the BUS you will multiple problems for years to come. Especially if the open or grounding or shorting is intermittent.

Wiring diagrams required obviously

 

[Showkey]

Wiring diagrams required obviously

And the ability read them and don’t make a simple mistake like red with white strip vs red with yellow strip.

That brings up that the DIY guy is going to have real trouble finding a shop manual and ETM as they are usually found by subscription, time limits and fees........printed manuals are thing of the past for most newer models.

 

[Wrench97]

Go look up a wiring diagram. There should be exposed points in the circuit that allow you to check without poking holes in the wiring. If you want to, you can buy inexpensive wire tracing tools like this one.

https://www.princessauto.com/en/auto-circuit-tracer-detector/product/PA0008415002

If you are already invested into a power probe, a wire tracing accessory is available.

https://www.aeswave.com/ECT3000-Circuit-Tracer-p9502.html

But bottom line, I've heard of at least one professional mechanic say that it's just quicker to work your way up the wiring with a test light.

We had a vender in Jersey that had that attitude cost us thousands of dollars in down time and repairs in wiring over the years since, small hole in wire allows road salt in and rots the wire from the inside. It's never a good idea to pierce even liquid tape and regular tape will only slow the process.
There is always a connector to disconnect and then visual inspection, if you don't see anything do a overlay between the connectors.

 

[2ndGearRubber]

Piercing does have its place, but extremely rarely. Obviously the wire needs repaired after the fact. But there are some situations where the only way that job is getting done, is piercing a wire.

For the OP: Back-probes and a volt meter will likely produce what you're looking for. One can also disconnect the component, and use a test light, or carefully front-probe the terminal making sure not to bend male terminals nor spread female terminals. A power probe is nice, but requires self control not to just inject power or ground into random circuits.

 

[Professional Tool User]

And the ability read them and don’t make a simple mistake like red with white strip vs red with yellow strip.

That brings up that the DIY guy is going to have real trouble finding a shop manual and ETM as they are usually found by subscription, time limits and fees........printed manuals are thing of the past for most newer models.

You'd be surprised at what you can find in terms of wiring diagrams on car forums.

 

[Professional Tool User]

We had a vender in Jersey that had that attitude cost us thousands of dollars in down time and repairs in wiring over the years since, small hole in wire allows road salt in and rots the wire from the inside. It's never a good idea to pierce even liquid tape and regular tape will only slow the process.
There is always a connector to disconnect and then visual inspection, if you don't see anything do a overlay between the connectors.

You just ignored the context of my post which was looking for parts of the circuit that are exposed or can be disconnected for testing. I was implying that checking with a test light without poking holes can be faster than using a wire tracing tool.

 

[Wrench97]

You just ignored the context of my post which was looking for parts of the circuit that are exposed or can be disconnected for testing. I was implying that checking with a test light without poking holes can be faster than using a wire tracing tool.

No I got what you were saying I highlighted the part about probing to keep others from thinking that's how professionals do it...................

 

[richfinn]

No I got what you were saying I highlighted the part about probing to keep others from thinking that's how professionals do it...................

You have to bear in mind the context of peoples posts

For example if you are working on a rotten peice of junk worth $1500 and your options are remove the dashboard to get at a connector or pierce a wire for a test and reseal with liquid electrical tape

I know which one the customer is choosing

This is sometimes the reality for most "professionals" (you get paid to fix stuff)

 

[overkill19]

I absolutely love my power probe. But they are not cheap and being able to charge 12v to the probe is not for everyone... you can fry a lot of stuff if ur not careful.


Sent from my iPhone using Tapatalk Pro

 

[pepi]

You have to bear in mind the context of peoples posts

For example if you are working on a rotten peice of junk worth $1500 and your options are remove the dashboard to get at a connector or pierce a wire for a test and reseal with liquid electrical tape

I know which one the customer is choosing

This is sometimes the reality for most "professionals" (you get paid to fix stuff)

Is there a discount for hacking/butchering do the PRO's offer that?


Bad habits are bad habits, hack/butcher a 1500 piece of junk, taking 10 min of labor. Caddy comes will get the same repair x2 PRO labor rate.


One way to fix stuff, the right way. Shade tree repair for the 1500 junk, is also used for the 50K customer..

 

[richfinn]

Is there a discount for hacking/butchering do the PRO's offer that?


Bad habits are bad habits, do it one a 1500 piece of junk, taking 10 min of labor. Caddy comes will get the same repair x2 PRO labor rate.

A Caddy is a $1500 piece of junk where I come from

 

[Buckaroo5]

Standard automotive technique - flexible back probe pins with multimeter. Probe the back side of the connector where the wire enters. No damage/no pierced wires.

https://www.fluke.com/en-us/product/accessories/probes/fluke-tp40

 

[Djosbun]

Hi all,

I’m looking for an automotive voltage tester that can tell me if I have a hot wire without puncturing the wire insulation.

Bonus points if it can tell me the actual voltage, as I think sometimes the voltage is 5v and sometimes 12v for what vehicles I have.

Thanks

It depends on what you're measuring. Some sensors receive 5 volts from the ECU, some receive 12 volts. Get yourself some back probes or T-pins and use your DMM.

-- Dave

 

[Ign]

Around 25:00 here Eric O pierces a wire for testing and speaks of his success with liquid electrical tape.

About 29:00 he has to pierce a second one and says something about the "anti-wire-pokers" are gonna go nuts.

I was initially looking for a different vid on a Chevy truck that was towed to him after another shop had massacred the harness trying to trace a fuel pump problem -- by then the harness was practically Swiss cheese with holes in multiple locations. But I couldn't find it.....that was also a cool vid where he was using his own custom 1157 etc test stuff to see if a circuit could withstand a given load and I learned something there for sure

 

[richfinn]

Around 25:00 here Eric O pierces a wire for testing and speaks of his success with liquid electrical tape.

About 29:00 he has to pierce a second one and says something about the "anti-wire-pokers" are gonna go nuts.

I was initially looking for a different vid on a Chevy truck that was towed to him after another shop had massacred the harness trying to trace a fuel pump problem -- by then the harness was practically Swiss cheese with holes in multiple locations. But I couldn't find it.....that was also a cool vid where he was using his own custom 1157 etc test stuff to see if a circuit could withstand a given load and I learned something there for sure

Eric O lives in the real world, sometimes you have to do it, liquid tape is great, I always clean and mark the insulation before I have to pierce the insulation, so I can accurately repair the tiny hole left by the Pomona probe

I have seen a lot of butchered weatherpack style seals in multiplugs after dealerships have attempted to diagnose faults!!!!!

You can also inadvertently "temporarily fix" intermittent poor connections going for the plugs

 

[unslow1]

Bernie on Automotive Test Solutions videos seems to have the same opinions on piercing being the least invasive in a lot of situations.

 

[richfinn]

Bernie on Automotive Test Solutions videos seems to have the same opinions on piercing being the least invasive in a lot of situations.

His videos are excellent, very clever guy and his diag process is one of the best I've stumbled across on YouTube

 

[pontoon]

I absolutely love my power probe. But they are not cheap and being able to charge 12v to the probe is not for everyone... you can fry a lot of stuff if ur not careful.


Sent from my iPhone using Tapatalk Pro

I’ve thought about a power probe. So far I’ve always been able to use my multi meter so I haven’t pulled the trigger yet.

So I looked into those non contact high voltage AC test lights and was hoping something like that existed for automotive. It seems like from the sound of it such a thing does not exist.

I’ve never used a test light. Is it just a probe you pierce the hot wire with and it lights up if it’s got voltage? If so it seems like my multi meter can already do what the test light does.

I do have wiring diagrams for all my vehicles. In some cases I can read it correctly (some are a bit complicated for me). Sometimes I just want to get something done fast and just want to find the hot wire fast. Even if I read the diagram I usually would like to confirm what I’m reading before I start chopping up the wiring and adding new circuits.

So it sounds like options are:
- pierce the wire and repair it, with the issues mentioned above
- front probe
- back probe
- make a breakout connector and measure that (don’t always have the correct connector)

Am I missing anything?

 

[2ndGearRubber]

Those are the main methods. What are you trying to accomplish? Ideally you just unplug the component and inspect from the connector. Are you trying to steal power from another circuit to send elsewhere?

 

[pontoon]

Those are the main methods. What are you trying to accomplish? Ideally you just unplug the component and inspect from the connector. Are you trying to steal power from another circuit to send elsewhere?

Yes most of the time I’m trying to do a mod like adding a dash cam, adding a usb charger, back up camera, extra lights, etc. For that at minimum I need to find power and sometimes a ground wire (sometimes I add or use existing earth ground).

 

[dscheidt]

I’ve never used a test light. Is it just a probe you pierce the hot wire with and it lights up if it’s got voltage? If so it seems like my multi meter can already do what the test light does.

A test light is a light bulb, with some wires on it. One end to ground, the other to power, it lights up. That's faster for a lot of things than using a meter, and easier to see in awkward positions. The other very useful thing you do with a test light is provide a substitute load. by choosing the size of the bulb in the test light, you can test that a circuit can provide that current. A typical store bought test light is 200 mA or so. One using a turn or tail light bulb is 1A, one using a headlamp is 4A give or take. you match the test load to the device being tested.

A meter just tells you there's voltage, but that doesn't mean the wire or driver can provide current. Say you're testing a no crank. Early on the list of things to check is that there's voltage on the starter solenoid control wire when the key is in crank. you can have a damaged wire, that will show battery voltage if you disconnect it, and measure, but if you hook a 4a test light, it won't light or will be very dim, because there's too much resistance in the damaged section.

 

[2ndGearRubber]

Yes most of the time I’m trying to do a mod like adding a dash cam, adding a usb charger, back up camera, extra lights, etc. For that at minimum I need to find power and sometimes a ground wire (sometimes I add or use existing earth ground).

Depending on draw of the device, just steal from the fuse box, or run a dedicated power from the battery, and individual grounds for the device.

 

[pontoon]

Depending on draw of the device, just steal from the fuse box, or run a dedicated power from the battery, and individual grounds for the device.

Yeah that’s also a good option sometimes. Sometimes I’m doing this on a motorcycle which doesn’t have much of a fuse box. Or on my truck the fuse box and battery may be kind of far away. I like to do smaller runs if I can just to keep things tidy and looking factory. I’m not a huge fan of stacking a half dozen terminals on the + battery. Another consideration is often I want switched power.

 

[2ndGearRubber]

Yeah that’s also a good option sometimes. Sometimes I’m doing this on a motorcycle which doesn’t have much of a fuse box. Or on my truck the fuse box and battery may be kind of far away. I like to do smaller runs if I can just to keep things tidy and looking factory. I’m not a huge fan of stacking a half dozen terminals on the + battery. Another consideration is often I want switched power.

IME motorcycles are conducive to grabbing off the battery. Or from the junction into the fuse box, then adding in line fuses per component. For heavily added-onto vehicles, a sub fuse box connected to the battery, with multiple circuits available is ideal. You could even run a main power supply off the battery and into the car, as though you where feeding an audio amplifier. Then, run it where you like, into an aftermarket fuse box, and do your branching there.

https://www.amazon.com/dp/B08H4Q9SYR/?tag=atomicindus08-20

First result on a search, no affiliation, just explains what I'm talking about. Gives you a fighting chance of things being manageable.

 

[Ign]

I like the Mac test light with connections for ground and power. You don't have to use both but if you do you get notified of grounds (green light I think) and hots (red IIRC?)

I know it's similar to a Power Probe but has advantages and arguably disadvantages. More than one way to skin a cat..

 

[pontoon]

IME motorcycles are conducive to grabbing off the battery. Or from the junction into the fuse box, then adding in line fuses per component. For heavily added-onto vehicles, a sub fuse box connected to the battery, with multiple circuits available is ideal. You could even run a main power supply off the battery and into the car, as though you where feeding an audio amplifier. Then, run it where you like, into an aftermarket fuse box, and do your branching there.

https://www.amazon.com/dp/B08H4Q9SYR/?tag=atomicindus08-20

First result on a search, no affiliation, just explains what I'm talking about. Gives you a fighting chance of things being manageable.

I ride dirt bikes and dual sport motorcycles. Very few people opt to run supplementary fuse boxes on the bikes I own.

I know about these fuse boxes. I’ve seen some nice ones used on restorations of old street bikes.

I run one accessory direct to battery and typically everything else I run is switched. Some guys use a relay for even more assurance the accessory won’t drain the battery. I ride far out into remote places including the desert. I need reliable wiring that won’t kill my battery. I also need minimal wiring since there isn’t a lot of room to run a bunch of extra wires. Different strokes for different folks, and I already know how I want to wire things. I’m just trying to figure out how to make life a little easier to find the right power wires.

 

[pontoon]

I like the Mac test light with connections for ground and power. You don't have to use both but if you do you get notified of grounds (green light I think) and hots (red IIRC?)

I know it's similar to a Power Probe but has advantages and arguably disadvantages. More than one way to skin a cat..

Yeah that is cool, I like the simplicity of the light colors.

 

[Ign]

For those who care if you go to ~9:00 you can see the Mac test light in action, green/red

 

[BigMike782]

That's a very cool test light!

 

[unslow1]

Mike Becker does videos on a lot of different channel names. He does do them well so I see why people want him.