How to perform a Starting System Voltage Drop Test

Voltage drop test will help find unwanted resistance within the circuit. Performing a voltage drop test will pinpoint the source of the fault. Inalso used a thermal imaging gun to prove that the multimeter will not lie if test is done properly.

[@carlosdelossantos7212]

Señor I don't remember seeing that thermal imaging gun when I was in your Class. Very nice explanation. Being comfortable with the meter and understanding what test you're performing will help pinpoint the problem every time. Good stuff sir.

[@rolandsmith2141]

My auto electrical skills are not very good videos like this are so appreciated and enjoyable, thanks mate

[@davidparker9676]

Takes me back to Trade Tech days. Very well demonstrated and explained. The FLIR camera really helps speed up diagnostics like this.

[@MAZMSPBRA]

Amazing explanation!!! Straight and clear with the test procedure!

[@cbarkwell1000]

EXCELLENT Voltage Drop Testing method...Your only MAJOR Fault is that you didn't tell the Public where both ends of the Green Jumper wire were connecting too to partially Crank the Engine.

[@transmitterguy478]

Great video! I'm a Certified Electronic Tech and never thought to check my own truck for voltage drop on the starting sequence. Thanks.

[@bwasman8409]

Very well done presentation! I've watch many that lose me through their's. Keep up the good work!

[@nickayivor8432]

Welcome back, MR DIAGNOSTECH 👍 SHREWD, MR DIAGNOSTECH From Nick Ayivor from London England UK 🇬🇧 07:39AM Good Morning 🙏 🌄

[@1231234abcab]

Very good explanation 👍🏽 The thermal imaging gun is a nice addition to the diag tools !

[@bobcote4893]

Excellent video. Thanks. It would also be helpful to show how you are cranking the engine.

[@8power0]

VERY GOOD EXAMPLE ,,, THANKS FOR YOUR TIME !!!!!!!!!!!!!!!!!!!!

[@stationaryenginesworldwide]

Great video sir ! Very well explained ..looking forward to more .

[@garylewis3641]

Very good video, enjoyed it!

[@MukeshSingh-xy7cz]

Thanks for a flawless and finely explained video. Iam a electrical auto mechanic. I haven't come across such a video. Keep it up sir

[@MRDIAGNOSTECH]

Thank you very much. I'll keep uploading more videos more frequently.

[@ShahzadShahzad-eo2ix]

Very good explanation thanks

[@Charles_S.]

Very well explained 👍

[@ThunderbirdRocket]

That’s great ! Thanks for sharing this lesson with us !!

[@ritchieschofield1185]

That's a healthy battery!. Great video

[@mohammadbenattia9102]

Thank you

[@jeffg1149]

Really should be attached to the post. If there was a poor connection at the battery this way would miss it

[@naseembeg5396]

Nice video

[@shakeelsss]

Do you give one on one session on how to read wiring diagrams?

[@huupham1025]

Great video! I wonder why you do not test the resistance so you do not have to crank the engine.

[@MRDIAGNOSTECH]

That's because it passed the resistance tets. A bad wire could still pass a resistance tets. The best reliable test is to perform a voltage drop test while current flows on any electrical circuit.

[@joehead1294]

The resistance is too low to measure. E=IxR For example 500 millivolts divided by 150 amps equals 3 milliohms. Or 150 amps times 3 milliohms equals 450 millivolts. But you need two of the three values to calculate. Not sure what the amp draw was in this test. I'm just using a value for the formula. Ohm's law.

[@jordysandino6577]

Hello sir . Great video . When do you perform that test ? What’s is wrong with the car ? I’m trying to learn . Please forgive my ignorance

[@MRDIAGNOSTECH]

This test is performed on a vehicle that has a slow crank wich could be caused by weak battery, bad starter motor, or in this case unwanted resistance on wires and connections.

[@jordysandino6577]

Thank you so much sir . Please keep posting videos cuz we want to learn more about vehicles diagnostics

[@drazenaudi7864]

Svaka čast na jasnom objasnjenju....pozdrav iz Hrvatske.

[@trygveseljeflot6245]

Forgot to test voltage drop over solenoid contacts ?

[@joelopez40oz23]

Did this vehicle have any symptoms? I noticed cranking sounds normal.

[@MRDIAGNOSTECH]

No symptoms because it had an 800CCA battery, strong enough to crank the engine without issues. This issue could cause a slow crank.

[@rambleon2838]

What does determine the amount of voltage drop being acceptable?

[@MRDIAGNOSTECH]

Positive side: 0.500v Negative side: 0.200V

[@rambleon2838]

@@MRDIAGNOSTECH Is this manufacturer specific or in general for 12V systems? Thank you.

[@MRDIAGNOSTECH]

@rambleon2838 This are standard specs for electrical circuits.

[@rolandos64]

Voltage Drop = Potential Difference (Merely means, If you looked in your pockets, pulled out Your money, then emptied out Your Friends Pocket. What is the difference between Him and You. EX. You have $5.00. He Has $10 dollars. The Difference is $5.00. He Has $5.00 More than You.) under load on the same side!!! Its like testing a wire for continuity. Your DMM should read close to zero. You should see NO to little difference in Voltage/Pressure on one end vs the opposite End. Take Your $5.00 dollars from One Pocket, Place them in the opposite Pocket, youll Still have $5.00