EEVblog Electronics Community Forum
Electronics => Beginners => Topic started by: Winchmore on October 09, 2013, 09:57:11 pm
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Hi,
Can you recommend a very good multimeter for continuity testing for car wiring harness.
I was looking for a tool to test the continuity on two points where one point the wire is insulated. without having to pierce the wire. i.e brown wire in attached picture
I guess there wont be one without piercing the wire so next best thing will be using back probes...
Any good ones for continuity testing with good sound and back probes
up to $100. will use for other general tasks etc Any old trusted models on ebay fine.
Rgs
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There are two separate issues: What meter should you use, and what probes should you use.
If you're only doing continuity detection, it's hard to imagine a meter that won't do the job. A lot of people, myself included, like the Fluke-style latching continuity detection, because it delivers a good solid audible beep even with a very brief contact. Dave has demonstrated this well in some of his fairly early multimeter shootout videos. Some cheap meters have slow response in continuity mode.
I don't have enough experience with bargain meters in continuity mode to make specific recommendations.
As far as probes go, as long as your meter uses standard shrouded banana jacks, you can use any standard banana probes. There are several makers of good test probes with the standard telcom style "bed of nails" clips on the end. Fluke makes their MT-8203-20, which is one option, but similar products are available from other manufacturers.
For this particular application, I can imagine spending as much on the test leads as on the meter. Great leads combined with a really cheap meter should do the job well, while a superb meter outfitted with standard style leads wouldn't be so great.
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Another option is to use a wire tracker. For example
http://www.ebay.com/itm/Automotive-Cable-Wire-Tracker-Tester-Car-Tracer-Finder-/190505326904 (http://www.ebay.com/itm/Automotive-Cable-Wire-Tracker-Tester-Car-Tracer-Finder-/190505326904)
Some are better than others.
You connect to the wire on one end and trace along the wire.
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If its attached to a car look at Power Probe. It can read 5 or 12 volts and inject voltage. Hard to explain.
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Many thanks for the response and ideas Zapta & AG6QR!
I did start off looking at auto specific tools with the sound alerts. Was not sure if a multimeter reading would be significantly better then a sound alert tool. So if the contacts over time have been corroding, the signal strength would be reduced and hence looking for measuring tool to display this data if that's possible...
Fluke entry model sounds good that can do the job. Fluke 101?
Will have a look at the Automotive Wire Tracker Tester Car Tracer Finder..
Stonent, Power Probe also sounds good....is this Power probe 3?
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My experience with multi meters for checking car wiring is that they give false positives which will have you running all over the place looking for faulty equipment and even replacing items the appear not to work. The reason, not enough burden voltage, you check a supply line for voltage get a nice 12 something volts and think thats fine, its not all to often you get corrosion on connections that allow small currents but not enough to work a bulb or motor or whatever but still give you a full voltage reading on the wire when you disconnect to take a reading the same goes for continuity checks on the earth or return points enough power will flow to set of the buzzer in the meter but it still has two high a resistance to allow the equipment to work.
A good tool to have for chasing down car faults is one of these units.
http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e (http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e)
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My experience with multi meters for checking car wiring is that they give false positives which will have you running all over the place looking for faulty equipment and even replacing items the appear not to work. The reason, not enough burden voltage, you check a supply line for voltage get a nice 12 something volts and think thats fine, its not all to often you get corrosion on connections that allow small currents but not enough to work a bulb or motor or whatever but still give you a full voltage reading on the wire when you disconnect to take a reading the same goes for continuity checks on the earth or return points enough power will flow to set of the buzzer in the meter but it still has two high a resistance to allow the equipment to work.
A good tool to have for chasing down car faults is one of these units.
http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e (http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e)
Thanks that makes a lot of sense.
have ordered the tool :)
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But if you still need a good multimeter under $100 with great continuity test, I suggest you get UNI-T UT61E. You have reviews here on forum and Dave did an episode on sub USD100 multimeters where he recommends UT61E out of all. Based on his suggestion I got one and I am very pleased with it.
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I don't think Dave ever reviewed the UT-61E. Don't confuse the dozens of Uni-T models, there seem to be some large differences in quality between models. The meter Dave reviewed had a very slow continuity response, for example. So does the UT-71E I think.
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My bad, it was UT61D model that Dave did comarison on, and UT61D has terrible continuity - EEVblog #99 - $100 Multimeter Shootout - Extech Amprobe BK Precision Ideal UEi Uni-T PART 2of2 (https://www.youtube.com/watch?v=3-_dUB8vy8U#ws)
Martin did a review on UT61E Multimeter Review / buyers guide: Part 2 - UNI-T UT61E (https://www.youtube.com/watch?v=5YbbbgbJK9I#ws)
I have UT61E and I am very pleased with it. Just got a 6 1/2 digit voltage reference and UT61E is spot on every value. Most UNI-T products are mislabeled and bad in some repsects, but I like UT61E very much. I'm still a beginner and hobbyist so I can't really afford big brands and expensive multimeters.
p.s. I have been following Dave for years, but just registered a month ago when I just got a grip on electronics in general and once I had some knowledge. Didn't wanna bother with stupid questions earlier :D
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If you are looking for intermittent [ open or short ] in the loom, and feel like making one, have a look at this project
http://www.sentex.ca/~mec1995/circ/latching.html (http://www.sentex.ca/~mec1995/circ/latching.html)
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I like this one : doesnt inject too high voltage in the circuit...
http://elm-chan.org/works/cch/report_e.html (http://elm-chan.org/works/cch/report_e.html)
(http://elm-chan.org/works/cch/cc.png)
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My experience with multi meters for checking car wiring is that they give false positives which will have you running all over the place looking for faulty equipment and even replacing items the appear not to work. The reason, not enough burden voltage, you check a supply line for voltage get a nice 12 something volts and think thats fine, its not all to often you get corrosion on connections that allow small currents but not enough to work a bulb or motor or whatever but still give you a full voltage reading on the wire when you disconnect to take a reading the same goes for continuity checks on the earth or return points enough power will flow to set of the buzzer in the meter but it still has two high a resistance to allow the equipment to work.
A good tool to have for chasing down car faults is one of these units.
http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e (http://www.ebay.co.uk/itm/CAR-CIRCUIT-VOLTAGE-TESTER-6-12-24V-WITH-ALLIGATOR-CLIP-/400527474990?pt=UK_Diagnostic_Tools_Equipment&hash=item5d414c412e)
You can hang a low value resistor across the meter,to reduce its input impedance.
I know!-----It's messy! ;D
The false positive with the continuity function is why I very seldom use it---I just read the actual resistance,retro style.
El Cheapo DMMs take forever to beep,but even with a decent meter,if I have to use it,as sometimes,you do,I still don't trust it.
It is good for checking diodes & transistors,though!
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I very seldom use it---I just read the actual resistance,retro style.
I am with you, but for different reasons: in the modern days where you have to manage gadgets and their ever dying rechargeable batteries, I developed a hatred for beeps!
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Thanks for the above will check them out :)
This looks the part..not sure how its managed without piercing the wire...
http://www.ebay.co.uk/itm/Multi-function-Auto-Circuit-Tester-/130738908535?pt=Motors_Automotive_Tools&hash=item1e70a56d77 (http://www.ebay.co.uk/itm/Multi-function-Auto-Circuit-Tester-/130738908535?pt=Motors_Automotive_Tools&hash=item1e70a56d77)
http://www.ecutool.com/multi-function-auto-circuit-tester_9823.html (http://www.ecutool.com/multi-function-auto-circuit-tester_9823.html)
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hi
buy a CEM DT-337 and have a 4A and 80A dc for really interesting extras
usefull in car wiring
alligator clip +long wire + 2 batteries a resistor an a led cant be beaten