We always here about voltage drop in the classes we go to but does it ever really apply to fixing cars? It is always taught but never really shown in real life examples. Well any one who watches my channel knows I have shown in several videos why it is so important and how to use your meter to see the "pressure" difference between two points. Hear yet again is another example.
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If an SMA Video has helped you out please consider giving using "Patreon" to help support us. The videos take real time to create and pull us away from real work that pays our bills. CLICK HERE: https://www.patreon.com/southmainauto
CHECK OUT OUR "SMA SWAG" STORE! Go on Teespring and get your very own SMA merch!
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Thank you for all the continuing support!
--Eric & Vanessa O.
Feel like sending some swag to SMA because you love the videos but don't know where to send it?
Just ship it here:
South Main Auto Repair
47 S. Main St
PO Box 471
Avoca, NY 14809
Disclaimer:
Due to factors beyond the control of South Main Auto Repair, it cannot guarantee against unauthorized modifications of this information, or improper use of this information. South Main Auto Repair assumes no liability for property damage or injury incurred as a result of any of the information contained in this video. South Main Auto Repair recommends safe practices when working with power tools, automotive lifts, lifting tools, jack stands, electrical equipment, blunt instruments, chemicals, lubricants, or any other tools or equipment seen or implied in this video. Due to factors beyond the control of South Main Auto Repair, no information contained in this video shall create any express or implied warranty or guarantee of any particular result. Any injury, damage or loss that may result from improper use of these tools, equipment, or the information contained.
GREAT INFO THANK YOU
should you disconnect the negtive post of the battery while you are working on the positive side of the battery?
What do you think of the LoadPro for this application?
these reminders are so good glad you took the time to show
This guy needs to do schooling , love to have as a teacher ! 👍👍👍
I just found this channel, pure gold the way you analyze the facts with a meter instead of throwing parts or using a simple jumper. Quick question, based on the comment about heat and resistance. How hot should an alternator get? I know its on an engine but most times there is air flow around an alternator. Should it be too hot to touch under normal circumstances or would that be an indication of an issue?
What about grease on terminals and connection points. Is that just a tale from the olden days or is there some validity to it. I was told that dielectric grease on terminals will eliminate the potential for this sort of issue. Same with connection points, clean and a tad of grease will keep the connection point from crusting up .
All the stuff South Main Auto demonstrates / teaches is GREAT STUFF 👍😊 YOU have many , many years of PROVEN EXPERIENCE and vehicle repair knowledge and when I watch you make repairs and you say – if I can do it – you can do it – I'm STOKED 😊 Again – GREAT INSTRUCTION , I learn something from every video you make – MANY , MANY THANKS and , no doubt , if I lived near you – I would surely bring my vehicles to your shop for repair and ABSOLUTELY REST ASSURED – knowing you would repair it properly. ✌️✌️✌️
Can fluid leaks, say from a bad O ring on a coolant line to the radiator, affect wire grounds or wire connections? BD
can i create a load in a circuit for somthing like starter that doesn't have current flow with a lightbulb? could i hook a light in the circuit so it can be tested?
i understand a light will only draw around a few amps but if you have a voltage drop in the wire wouldnt it i be able to see it via creating a load with light so i can voltage drop test? or a cheap way to load up the circuit so i can perform the test.
Good Morning South Main Auto Repair
Very KNOWLEDGEABLE
Thanks 👍
From Nick Ayivor from London England UK 🇬🇧
now really this should be called a resistant test on voltage ??? meaning lack of voltage getting through the cables or connections??? and it could be called a voltage loss ??? but not really a loss,,, because the voltage is not really loss,,, it is there but not getting through to the other side, remember this: ( Most Electrical problems are resistant by nature and occur at connections ),,, My College Teacher made the whole class say this at the start of every class for 2 years… i think he was a great teacher 27 years he taught in a college…
Another Great Video…
Just want to say thank you for sharing your knowledge. God bless you
Great information. I am studying for ASE certification and on the study guide I’m learning about voltage drop. This brings me to a question. I noticed that you connected the meter leads to the source in question and then cranked the engine, read the meter, and stoped cranking. My question or confusion is that the ASE study guide says to remove the lead from the battery post before you stop cranking the engine to avoid damaging the meter. I see that you did not do that. Is it even necessary to do so in that case?
Can any one help me understand voltage drop I don’t understand the multimeter readings what you should be reading on the meter when testing for a voltage drop but I understand what is meant by a voltage drop when something is not working
Even if not knowing anything about electrical connections, as in the invisible film that forms between a battery post and its terminal that will keep a battery from delivering the power, it befalls me that an idiot who replaces a battery would not automatically clean ALL connections to shiny metal!!! period. idiots! but then one should do that before replacing the battery and avoid to buy a new battery that is not needed.
Great explanation on Voltage drops.. I'm having a real world situation right now, it's a 93 Ford Ranger with the 3.0L V6, with ignition off I have around 13v, ignition On (on run position) drops down to 9v I try to crank it and no joy, put an amp meter in series with the negative cable and battery post and I'm looking at 4.5amp draw mainly because the FP is on all the time, but still having 9v with ignition on, any suggestions?.
258000 miles on a northern car,I thought all those northern car rusted and fell apart right after 100000 miles
But love your Channel keep up the good work and yeah you might make a good teacher probably easier on that old back and more money
Great video. Thank you Eric. Measuring the temperature is a great ideal.
Great video I just wish you would mention what the readings you are finding should be, for instance, you should see no more than .5v voltage drop on the ground side or the positive side
So… The voltage drop from the positive cable clamp to the positive battery post must be equal to 0V? Why?
one of the first things I was told / learnt as a 17 yr old was battery terminal corrosion … barcbonate of soda in solution pour over dismantled parts is a solution … or was that baking soda
Excellent
Good explanation there Eric. Thanks
Even a blind technician at Wal-Mart could have seen the dirty cable was an issue
so someone really took those terminals off to replace both batteries, and changed a starter and didn't once think to maybe clean the terminals? wild.
Great job. Maybe I can find out why I keep getting a PO562 code on my PT Cruiser!
On starting engine after fixing battery problem the Engine Light was on. Other problems.
All the connections need to be replaced.
Just subbed your videos are a wealth of knowledge. I just picked up an 07 nbs silverado and I got it dirt cheap has been to several shops with no improvement for the previous owner no communication between any modules with blue driver scan tool drove it home with only 1st 2nd 3rd gear it slammed every gear when shifting, terminating resistor checked out at 120 ohm I was at a loss ended up pulling both fuses for the abs and got communication back with all modules except the abs module of course but when I put the fuses back in I got communication with the abs module but I get codes for all the wheel speed sensor circuits I'm at a loss now I have to check all the wires I guess before I condemn the abs module itself still doing research for that.
Jumpers go around the issues to start. A voltage drop will locate the issue so that you can replace a failed part.
Thank you SMA.
Another great job explaining voltage drop testing. Keep making these videos!
Nice, video is great
This maybe a dumb question, but could you ohm these connections out to find these problems? Or is the voltage drop check the best way to find these bad connections?
Have question regarding voltage drop.
scenario 1.
Objective=To check the integrity of ground wires from the PCM.
-KOEOff ( reading 5 volts on ref) – circuit is on ( supposedly loaded)
hook up one lead to BAT (Neg)and the other lead to entry point at PCM connector ( connector is attached to PCM).
DMM reads 6.2mV.
Would such procedure establish if the circuit is good ( mainly to see if wire going into PCM is connected to ground and in good condition)
Can the LoadPro also perform this test, if so what are the conditions and hook up.
Someone suggested to disconnect PCM wire, use a test light. One side goes to BAT+ the other touch the ground PCM wire, if light is "bright" circuit OK.
I ask that you comment on the merits or lack thereof of each method, if possible
Thank you
Yeah, just throw the parts cannon at it with a blindfold on….luckely there are still mechanics like Mr O around.
Is it possible to connect the starter test button alligator clips to the positive and negative wires that connect into the battery fuse terminal that is connected to the battery positive post. This meaning, is it possible to disconnect the positive and negative starter wires from the fuse terminal block(the fuse terminal block is connected onto the positive post of the battery), and then attach the starter test button on the positive and negative wires? My vehicle is a Honda HR-V 2017 EX-L FWD. Thank you in advance for ready my comment.
I love your way of explaining your approach. Clear and to the point. I also appreciate you using a diagram. Great work! Subscribed and liked!
Really good explanation thanks! Especially good for me as I am doing an apprenticeship and this was a good video to learn voltage drop from.
Great diagnostic video. You used a solid technique for explaining the tests and how to perform them. Which snap on scanner did you use with graphing functionality…works great. Thank you
As someone who is still learning to work with voltage drops and electrical gremlins videos like this really help specially when you get ahold of vehicles that act crazy got an 89 mustang that tries to start and will start on its on as soon as the key hits on it just randomly quit happening still an unsolved mystery lol
Hi
I love your videos: informational and entertaining.
However: yours is the second video that states "a load" must be placed on the circuit before a voltage-drop test may be performed.
SITUATION:
I have a Freightliner Century Classic 120, Class 8 Tractor, where with NO load, I meadured 1.0-1.75 less volts on a ground side of a circiuit.
Whether this circuit legit OEM is a factor. A website says that 12 gauge AWA copper wire over 12 feet, like this foreign wire in this non OEM circuit, will drop to 11.82 from 12.5 volts. There is no load: just static battery voltage drop
What gives?
You're a great teacher. I just learned how to properly do a voltage drop test and what to look out for in your videos. And learned a whole lot more. My learning has been excelled from your channel. Amazing work. And amazing craftsmanship. Thank you!
the Cat phone 61 has thermal imigaging
Nice demonstration on how and why you should carry out a voltage drop. 👍
Well explained mate
Catchier title
"Truck suffers from crusty VD"