Bad Block Ground Diagnosis Using VOLTAGE DROP TESTING
ScannerDanner
42,547 views
This vehicle came in completely dead—no interior lights, no power, and no crank—even though the battery measured a healthy 12.6 volts. In this video, we walk through a real-world automotive voltage drop diagnosis and show how a bad engine block/body ground can shut down an entire electrical system. Using a digital multimeter, we trace a massive voltage difference between battery negative and the engine block back to a poor ground connection that had recently been disturbed. Along the way, we explain ground-side voltage drop testing, Kirchhoff’s Voltage Law, current flow, starter inrush current, and why intermittent electrical problems can be so difficult to diagnose when the fault isn’t actively occurring. If you’re learning automotive electrical diagnostics, no-crank diagnosis, bad ground testing, battery cable testing, or how to use a multimeter for voltage drop testing, this case study is packed with practical techniques you can use in the shop.
🔧 Looking for Deeper Training?
Whether you're a DIYer, an aspiring tech, or a working technician, ScannerDanner Premium gives you in-depth diagnostic training built around real testing and real troubleshooting:
👉 Join Here – 14 Days for $1
https://www.scannerdanner.com/join-sc...
On ScannerDanner Premium, you'll get:
*In-depth classroom lectures based on the material in my book
*Case studies with real vehicles brought into class
*Troubleshooting using proven diagnostic methods
*Access to our private forum
*Fundamental training in automotive electrical, electronics, and drivability diagnostics
📘 Want to Learn More About Diagnostics?
Check out my field manual, Engine Performance Diagnostics, available as both an eBook and paperback at:
👉 https://linktr.ee/scannerdanner
ScannerDanner Tools:
https://linktr.ee/scannerdanner
⚠️ Disclaimer:
ScannerDanner LLC is not responsible for misuse, unauthorized changes, or incorrect application of any information provided. Always follow proper safety protocols when using tools, equipment, or procedures discussed in this video. Use this content at your own risk.
0:00 – No Power, Initial Battery Testing
1:08 – Finding Voltage on the Engine Block
2:14 – Tracing the Bad Ground
4:24 – Confirming the Bad Connection
5:48 – Power Restored
7:41 – Voltage Drop Testing Explained
13:09 – Cleaning and Reassembling the Ground
14:19 – Cranking Test After Repair
15:35 – Starter Inrush Current Explained
17:00 – Final Wrap-Up
20 Comments
I learned this from you maybe 7-8 years ago I had an old Chevy pickup truck that I was reading voltage when I was touching different parts of the truck from the negative I couldn't understand it and then watching some of your videos I figured out I had a bad block ground but it's always nice to see a refresher.
Bad Block Ground Diagnosis Using VOLTAGE DROP TESTING
ScannerDanner
42,547 views
This vehicle came in completely dead—no interior lights, no power, and no crank—even though the battery measured a healthy 12.6 volts. In this video, we walk through a real-world automotive voltage drop diagnosis and show how a bad engine block/body ground can shut down an entire electrical system. Using a digital multimeter, we trace a massive voltage difference between battery negative and the engine block back to a poor ground connection that had recently been disturbed. Along the way, we explain ground-side voltage drop testing, Kirchhoff’s Voltage Law, current flow, starter inrush current, and why intermittent electrical problems can be so difficult to diagnose when the fault isn’t actively occurring. If you’re learning automotive electrical diagnostics, no-crank diagnosis, bad ground testing, battery cable testing, or how to use a multimeter for voltage drop testing, this case study is packed with practical techniques you can use in the shop.
🔧 Looking for Deeper Training?
Whether you're a DIYer, an aspiring tech, or a working technician, ScannerDanner Premium gives you in-depth diagnostic training built around real testing and real troubleshooting:
👉 Join Here – 14 Days for $1
https://www.scannerdanner.com/join-sc...
On ScannerDanner Premium, you'll get:
*In-depth classroom lectures based on the material in my book
*Case studies with real vehicles brought into class
*Troubleshooting using proven diagnostic methods
*Access to our private forum
*Fundamental training in automotive electrical, electronics, and drivability diagnostics
📘 Want to Learn More About Diagnostics?
Check out my field manual, Engine Performance Diagnostics, available as both an eBook and paperback at:
👉 https://linktr.ee/scannerdanner
ScannerDanner Tools:
https://linktr.ee/scannerdanner
⚠️ Disclaimer:
ScannerDanner LLC is not responsible for misuse, unauthorized changes, or incorrect application of any information provided. Always follow proper safety protocols when using tools, equipment, or procedures discussed in this video. Use this content at your own risk.
0:00 – No Power, Initial Battery Testing
1:08 – Finding Voltage on the Engine Block
2:14 – Tracing the Bad Ground
4:24 – Confirming the Bad Connection
5:48 – Power Restored
7:41 – Voltage Drop Testing Explained
13:09 – Cleaning and Reassembling the Ground
14:19 – Cranking Test After Repair
15:35 – Starter Inrush Current Explained
17:00 – Final Wrap-Up
Your videos helped me pass my L1 and A8 and A6
And has helped make a career working in a dealership where I strictly do electrical diag (which is exactly what I wanted)
Thank you