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.
What a very detailed video! Great job and thank you for taking the time to share it! I've watched several videos dealing with voltage drop, but by far, this one is the most detailed and comprehensive yet. Cheers
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.
How do you do the first test if your starter won't crank the engine at all Should a failed attempt aka just turning the keys still energize the circuit suitably for this test?
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 This test is performed when you have a slow crank condition and you suspect a possible bad starter motor, wiring, or engine. This test primarily check the condition of wires and connections for the starter motor circuit.
MR. DIAGNOSTECH, how did you cranked the engine from the fuse box? Nevermind, I think you had the key to the on position and jumped the starter relay terminal 30 and 87.
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.
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.
There was no need to, the TOTAL VOLTAGE DROP on the positive side was within specifications. If it wasn't then yes you are correct that would have to be one of the test points that should be checked.
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
Can you do voltage drop testing if the starter is not turning over (no crank)? When starting ignition (no crank) the voltage drop from (-) battery to starter housing is 78mv so good. My voltage drop from (+) battery to B-terminal jumps to OL. Its a new good starter. Starter relay is also good. The voltage drop from (+) battery to S lead is also OL when starting (no crank). ???
