1. Auto – Truck – H.Duty. Ground Circuit Voltage
Vehicle Electrical-Electronics Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas
Auto – Truck – H.Duty. Ground Circuit Voltage
By Vince Fischelli
Veejer Enterprises Inc., Garland, Texas Phone:
Web Site:
Copyright © 2017 Veejer Enterprises, Garland, TX

2. Ground Circuit Voltage – Review Main Points
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Part 10 of (?) Parts
Ground Circuit Voltage – Review Main Points
(1) Electron Current moves through a circuit in a negative to positive direction (- to +).
(2) Voltage is stationary at the voltage source and causes the electron flow through a circuit.
(3) No voltage = No electron flow (No water pressure = No water flow.)
(4) Lower voltage = Lower electron flow (Low water pressure = Low water flow.)
(5) Higher voltage = Higher electron flow (High water pressure = High water flow.)
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3. Voltage drops are NOT “Voltage Flow”
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Voltage drops are NOT “Voltage Flow”
(6) Voltage does not flow. Only electrons flow.
(7) However, because voltage drops appear around the circuit as electron current flows through resistance in the circuit, it is easy to misinterpret that fact as voltage moving (flowing) through a circuit.
(8) Wire has resistance which causes a Vd (Voltage drop) as electrons flow through the wire. Good wire = Low Vd
(9) Connections have resistance which causes a voltage drop as electrons flow through a connection.
Good connection = Low Vd
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4. Why does the DMM indicate 0.00?
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Why does the DMM indicate 0.00?
Fig. G01V
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5. Why does the DMM indicate 0.00?
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Why does the DMM indicate 0.00?
Fig. G02V
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6. Use –BATT (0.00V) for DMM Ground
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Use –BATT (0.00V) for DMM Ground
0.00V
Fig. G03V
Copyright © 2017 Veejer Enterprises, Garland, TX

7. Use –GEN (0.00V) for DMM Ground
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Use –GEN (0.00V) for DMM Ground
0.00V
Fig. G04V
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8. Verify Both –GEN and –BATT Are Good (0.00V) DMM Grounds
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Verify Both –GEN and –BATT
Are Good (0.00V) DMM Grounds
Fig. G05V
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9. Measuring Ground Side Voltage
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Measuring Ground Side Voltage
(Points to consider!)
Ground Voltage and the DMM (Voltage readings very small)
Which DMM do you have? (20 V – 30 V – 40 V)
The first thing to know about your DMM
The second thing to know about your autoranging DMM
Avoid DMM Confusion – Cancel Autoranging
0.01 = 10 mV (a pretty good ground Vd reading)
0.05 = 50 mV (maximum ground voltage drop for on-board computer ground)
0.10 = 100 mv (considered by ASE to be a good ground circuit)
mV or more (ground circuit beginning to experience corrosion)
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10. What To Do If Cleaning The Ground Connection Doesn’t Help
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
What To Do If Cleaning The Ground Connection Doesn’t Help
1. (Hint Resistance)
2. (Hint: Electron Current)
According to Ohm’s Law for “Vds” (Voltage drops)
E = I x R
E (Volts) = Amps x Resistance in ohms
E (Voltage drop) = Amps through the wire X Ohms of Resistance of wire
As electron current increases the Vd increases
E = 1.0 A x .05 ohm = 0.05 V (excellent ground Vd with normal electron current)
E = 2.0 A x .05 ohm = 0.10 V (acceptable ground Vd as electron current increases)
E = 5.0 A x .05 ohm = 0.25 V (ground Vd starts to increase due to higher amps)
E = 9.5 A x .05 ohm = 0.48 V (bad ground Vd due to high amps - not bad wire)
Copyright © 2017 Veejer Enterprises, Garland, TX

11. Remember Ground Side Vds
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Remember Ground Side Vds
0.01 = 10 mV (a very good ground Vd reading for all circuits)
0.05 = 50 mV (maximum ground side Vd for on-board computer ground)
0.10 = 100 mv (considered by ASE to be a good electrical ground circuit) mV (ground circuit beginning to experience corrosion)
Some circuits can operate with more Vd on the ground side than others.
Lamps, DC Motors, Solenoids will work with 0.30 as connections begin to corrode.
On-board computers work best with 0.05 V or less. No corrosion is tolerable with computer control grounds.
Copyright © 2017 Veejer Enterprises, Garland, TX

12. Validate Accessory Ground to Sheet Metal (1)
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Validate Accessory Ground to Sheet Metal (1)
Fig. G06V
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13. Validate Accessory Ground to Sheet Metal (2)
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Validate Accessory Ground to Sheet Metal (2)
Fig. G07V
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14. Veejer Enterprises, Garland, Texas
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
About Ground Straps…
Fig. G08V
Copyright © 2017 Veejer Enterprises, Garland, TX

15. What if the ground strap is missing?
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
What if the ground strap is missing?
Why reading of 3.19V?
What if reading is B+?
Fig. G09V
Copyright © 2017 Veejer Enterprises, Garland, TX

16. Accessory Ground Cable
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Measure Vd of
Accessory Ground Cable
Fig. G06V
Copyright © 2017 Veejer Enterprises, Garland, TX

17. Veejer Enterprises, Garland, Texas
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Validate quality of
Ground Strap
Fig. G07V
Copyright © 2017 Veejer Enterprises, Garland, TX

18. Veejer Enterprises, Garland, Texas
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Direct Measurement
Of Ground Strap
Quality
Fig. G08V
Copyright © 2017 Veejer Enterprises, Garland, TX

19. Missing Ground Strap Reading indicates another ground connection
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Missing Ground Strap
Reading indicates
another ground connection
is involved.
B+ reading indicates no ground at Sheet Metal (2)
Fig. G09V
Copyright © 2017 Veejer Enterprises, Garland, TX

20. Measure Ground Side Vds Both readings indicate good ground.
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Measure Ground Side Vds
Both readings indicate good ground.
Fig. G10V
Copyright © 2017 Veejer Enterprises, Garland, TX

21. Lamp Circuit #2 has a bad ground.
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Lamp Circuit #2 has a bad ground.
Title
Fig. G11V
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22. 5 Circuit Electrical System
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
5 Circuit Electrical System
Lamps are used as the electrical load in each circuit.
Loads could also be solenoids, DC motors, relays, etc.
Fig. G13V
Copyright © 2017 Veejer Enterprises, Garland, TX

23. Observe The Polarity Signs
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Observe The Polarity Signs
Fig. G13V+
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24. Practice Drawing the Polarity Signs
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Practice Drawing the Polarity Signs
Did you find all 17? (ignore BATT and GEN)
Fig. G13V
Copyright © 2017 Veejer Enterprises, Garland, TX

25. Trace Each Individual Circuit Voltage Side and Ground Side
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Trace Each Individual Circuit
Voltage Side and Ground Side
__ Lamp Circuit #1 __ Lamp Circuit #2
__ Lamp Circuit #3 __ Lamp Circuit #4
__ Lamp Circuit #5
Fig. G13V
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26. Ground Side Voltages Why is Circuit #5 Higher?
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Ground Side Voltages Why is Circuit #5 Higher?
3 Reasons 1. 2. 3.
DMM#1 DMM#2 DMM#3 DMM#4 DMM#5
0.04V V V V V
Fig. G14V-1
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27. DMM#1 DMM#2 DMM#3 DMM#4 DMM#5
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Ground Strap Failure
DMM#1 DMM#2 DMM#3 DMM#4 DMM#5
0.04V V V V V
Fig. G14V-2
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28. Unusual Reading at Circuit #4
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Unusual Reading at Circuit #4
What is DMM reading when S4 is OPEN? ______
Fig. G14V-3
Copyright © 2017 Veejer Enterprises, Garland, TX

29. Unusual Readings at Circuit #2.
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
Unusual Readings at Circuit #2.
What is DMM #1 reading when S2 is OPEN? ______ What is DMM #2 reading when S2 is OPEN? ______
Fig. G14V-4
Copyright © 2017 Veejer Enterprises, Garland, TX

30. This concludes the series on Ground Voltage Measurement
Vehicle Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises, Garland, Texas
This concludes the series on Ground Voltage Measurement
Electrical troubleshooting is easy when you know how!
Copyright © 2017 Veejer Enterprises, Garland, TX

31. The 1st Step- "Vehicle Electrical Troubleshooting SHORTCUTS"
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
The 1st Step- "Vehicle Electrical Troubleshooting SHORTCUTS"
The Vehicle Electrical Text Book:  Presents in 7 sections (250 pages) crucial electrical training for automotive and truck service technicians and students with hands-on shop exercises included. Do it all with just a DMM and Current Clamp!
Section 1 Essential electrical principles
Section 2 covers DMM's and Current Clamps
Section 3 How circuits work and electrical laws of circuits
Section 4 How batteries work and how to test a vehicle battery
Section 5 The cranking circuit and how to troubleshoot any cranking problem.
Section 6 How generators work methods to test and troubleshoot charging systems.
Section 7 Reading schematic diagrams
Review test after each section (answers in back of the book)
Visit our web site for more info!
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32. Veejer Enterprises Inc., Garland, Texas, USA
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
The 2nd Step - FIRST THINGS FIRST Two versions available (single battery and dual battery 14V systems)
Electrical flip-chart that shows a technician or student how to test and troubleshoot a vehicle’s primary electrical system consisting of the battery, major grounds and charging system in 14 test steps.
Do this FIRST: on any vehicle with
An electrical problem
An on-board computer problem
A driveability problem
Spiral bound with laminated pages.
Visit our web page & get all the facts!
Call or visit our web site for more info!
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33. How to Teach or Learn Auto/Truck Electrical Troubleshooting
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
How to Teach or Learn Auto/Truck Electrical Troubleshooting
Students or Technicians must learn how to troubleshoot electrical circuits. The vehicle industry desperately needs electrical troubleshooters!
Students or Technicians don’t really learn how by watching a video or somebody else doing it, although it does help to watch.
Students and Technicians best learn how to troubleshoot electrical circuits with hands-on application following a proven curriculum that allows them numerous hands-on opportunities to simply do it. Practice! – Practice! – Practice!
Here’s the Electrical Troubleshooting Curriculum
Visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

34. Electrical Troubleshooting Trainer
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
1st Hands-On Trainer - H-111A “The Starter Kit”
Electrical Troubleshooting Trainer
The First Step in learning how to troubleshoot an electrical circuit. Demonstrates with hands-on application how circuits work, how circuits fail and how to troubleshoot an electrical circuit to find the problem.
Contains 32 electrical problems for hands-on practice finding electrical problems in a circuit using a DMM.
Power Board H-PCB01 (top)
Lamp Board H-PCB02 (bottom)
Power Supply H-PS01 (supplied with kit)
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

35. Electrical Troubleshooting Trainer
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
H-111A “The Starter Kit”
Electrical Troubleshooting Trainer
Workbook H-WB111A guides students through exercises with hands-on practice covering circuit operation and circuit testing methods with a DMM.
Exercises include measuring circuit voltage, voltage drops and tracing voltage through the circuit. Electrical problems are inserted on the bottom of the circuit boards following guide-lines in an Instructor Guide. Troubleshooting is performed on the top of the circuit boards.
Call or visit our web site for more info!
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36. 2nd Hands-On Trainer - H-113 “Troubleshooting DC Motor Circuits”
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
2nd Hands-On Trainer - H-113 “Troubleshooting DC Motor Circuits”
DC Motor Electrical Trainer H-PCB03 demonstrates how DC Motor circuits work, how they fail and how to troubleshoot DC Motor circuits. Covers the new technology of Brushless DC Motors used as cooling fans, blower fans and fuel pumps. Also covers wire wound DC Motors used as blower fans and starter motors.
Provides 37 electrical problems to allow hands-on practice finding all the ways electrical problems occur in DC Motor circuits using a DMM and Current Clamp.
Call or visit our web site for more info!
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37. H-PCB03 Connected to the Power Board = H-113
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
H-PCB03 Connected to the Power Board = H-113
The DC Motor Board is connected to the Power Board for live testing and troubleshooting.
Workbook H-WB113 guides student through a series of hands-on exercises to measure circuit voltages and voltage drops to identify electrical problems at any place in a DC Motor circuit.
Electrical problems duplicate common DC Motor circuit failures that allow hands-on practice finding electrical problems using a DMM.
Power Board H-PCB01 (top)
DC Motor Board H-PCB03 (bottom)
Call or visit our web site for more info!
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38. 3rd Hands-On Trainer H-115 “Troubleshooting Relay Circuits”
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
3rd Hands-On Trainer H-115 “Troubleshooting Relay Circuits”
Relay Circuit Electrical Trainer H-PCB05 demonstrates how relay circuits work, how they fail and how to troubleshoot relay circuits.
Troubleshooting relays involves two circuits that have to be tested in the proper sequence which is explained. This program also covers the electronics of spike suppression diodes and testing the spike suppression diode with a DMM.
To add realism to the 75 relay circuit trouble-shooting problems the relay is called the Fuel Pump Relay and the lamp represents the Fuel Pump. The customer complaint for each problem revolves around a fuel pump circuit problem to connect students to the real world.
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

39. H-PCB05 Connected to Power Board = H-115
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
H-PCB05 Connected to Power Board = H-115
Relay Circuit Trainer H-PCB05 connects to the Power Board to complete the relay circuit for live relay circuit testing and troubleshooting.
Workbook H-WB115 with over 100 pages guides the student through relay operation, testing relay circuits and explaining the types of problems that occur in relay circuits. Provides 75 electrical problems to allow hands-on practice finding problems in relay circuits using a DMM.
Power Board H-PCB01 (top)
Relay Board H-PCB05 (bottom) connected to the Power Board.
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

40. 4th Hands-On Trainer H-PCB06 “Wire Harness Troubleshooting”
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
4th Hands-On Trainer H-PCB06 “Wire Harness Troubleshooting”
Power Board Here
Lamp Board Here
Relay Board Here
DC Motor Board Here
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

41. Creating the “Mini-Electrical System” = H-116
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
Creating the “Mini-Electrical System” = H-116
Wire Harness Electrical Trainer H-PCB06 creates a mini-electrical system to demonstrate how the wire harness connects all circuits together into an electrical system. Illustrates with hands-on how electrical problems affect individual circuits.
Provides 115 electrical problems to allow hands-on practice finding electrical problems related to a wire harness failure such as a broken wire or corroded connection.
“Mini-Electrical-System” (M.E.S.) Power Board H-PCB01 (top)
Lamp Board H-PCB02 (left)
Relay Board H-PCB05 (center)
DC Motor Board H-PCB03 (right) connected to the Power Board.
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

42. 5th Hands-On Trainer H-PCB06 “Wire Harness Troubleshooting”
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
5th Hands-On Trainer H-PCB06 “Wire Harness Troubleshooting”
There are two major areas technicians often overlook when attempting to repair CAN Bus system problems.
Problems in the network wiring that could exist when there is 60 ohms at DLC Pins 6 and 14.
Verify Nodes have good B+ voltage on all B+ pins and a good ground circuit on all B- pins.
These must be considered to repair many CAN Bus failures.
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

43. Fifth Hands-On Trainer CAN Bus Troubleshooting = H-200
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
Fifth Hands-On Trainer CAN Bus Troubleshooting = H-200
The CAN Bus Trainer is connected to the Power Board. A workbook, H-WB200, guides the student through troubleshooting the CAN Bus network to identify wiring problems even when Pins 6 and 14 indicate 60 ohms.
Troubleshooting training provides ample opportunity for students to understand CAN Bus issues and practice troubleshooting.
20 problems with broken wires and corroded connections in the 60 ohm network.
24 problems when a node has low B+ or high B- connections preventing normal operation.
CAN Bus trouble codes used to describe each problem.
Call or visit our web site for more info!
Copyright © 2017 Veejer Enterprises Inc, Garland, TX

44. Visit our web site for more information or to place an order.
Auto-Truck Electrical-Electronics Hands-On Troubleshooting Training Program
Veejer Enterprises Inc., Garland, Texas, USA
Visit our web site for more information or to place an order.
Call (972)
Home Page:
60 Lesson Electronics Course on-line:
Hands-On Circuit Board Trainers:
Book
“Vehicle Electrical Troubleshooting SHORTCUTS”
Electrical Flip-Chart FIRST THINGS FIRST
Copyright © 2017 Veejer Enterprises Inc, Garland, TX