Vehicle "How To" Test Guide CD

This technician's version covers the following:
Meters
How Accurate is Your Test Meter?
Understanding What a Voltmeter is Reading.
How to:

  • Set a Digital Volt Ohm Meter for Reading: Open Circuit Voltage, Charging Voltage, or Source Voltage.
  • Set the Digital Volt Ohm Meter, Leads, and Probes for Reading: The voltage drop between the battery positive (+) terminal and the input pin to any load on the vehicle.
  • Set the Digital Volt Ohm Meter, Leads, and Probes for Reading: The voltage drop between: the battery negative (-) terminal and the output pin or case ground from any load on the vehicle.
  • Set the Digital Volt Ohm Meter, Leads, and Probes for Reading:  The amount of source voltage available to any load on the vehicle.
  • Calibrate an Inductive Pick Up That Plugs into a Voltmeter.
  • Read a 100 millivolts per amp Inductive Pick up.
  • Make and Use a 10X Inductive Multiplier.
  • Extend Meter Leads When Testing a Long Distance From the Battery.

Battery Testing
How to:

  • Test the Voltage Drop Between the Battery (+) Post and Clamp.
  • Test the Voltage Drop Between The Battery (-) Post and Clamp.
  • Test the Open Circuit Voltage of the Battery.
  • Charge the Battery.
  • Do a Battery Load Test Using a VAT 40 or 45.
  • Do a Battery Load Test Without a Load Tester.
  • Find the Parasitic Drain on any Battery Using an Auxiliary Battery.
  • Do a 3 - Minute Charge Test on a Battery.
  • Test the Voltage Drop Between: the Battery (+) Terminal and the Starter Motor Armature Lead.
  • Test the Voltage Drop Between: The Battery Positive (+) Terminal and Fuses.
  • Test The Voltage Drop of a Battery Positive + Pigtail Wire.
  • Test Connectors and Connections of Positive + Pigtail Wires.
  • Test the voltage drop between: the wire and the clamp material in a battery positive (+) pigtail.
  • Test the Voltage Drop Between: the Battery Negative (-) Terminal and Where the Negative (-) Cable Attaches to the Frame or the Block.
  • Test the Voltage Drop Between: the Battery Negative Cable Conductor and its Connector.
  • Test the Voltage Drop Across a Suspect Negative Pigtail Cable or Wire Connector.

Computer/Module Testing
How to:

  • Test the Voltage Drop of Computer Voltage Feed Wires That Can Be Back-probed.
  • Test the Voltage Drop of Computer Ground Wires That Can Be Back-probed.
  • Load Test Computer Voltage Feed Wires.
  • Load Test Computer Ground Wires.

Continuity Testing and Ohmmeter Usage
How to:

  • Test for Continuity with an Ohmmeter.
  • Cautions When Using an Ohmmeter.
  • Tell if Solid State Components are Affecting Ohmmeter Resistance Readings.   ©   

Current Path, Connections, and Switch Contact Testing
How to:

  • Test the Voltage Drop of Any Length of Wire.
  • Test for Available Voltage to a “Hot at All Times” Connection.
  • Test for Available Voltage to a “Hot In Start or Run” Connection.
  • Load Test a “Hot at all Times" Connection.
  • Load Test a “Hot in Start or Run” Connection.
  • Test Any Mechanical Switch Using an Ohmmeter.
  • Tests the Voltage Drop of Any Mechanical Switch.
  • Test the Voltage Drop of a “Suspect Wire Connector”.

Fuse, Fusible Link, and Circuit Breaker Testing
How to:

  • Test the Voltage Drop Across a Fuse Connection.
  • Use a Blown Fuse to Direct Your Troubleshooting.
  • Find a Short to Ground (that resulted in a blown fuse), Using a Light Bulb Load.
  • Test Fusible Link Wire.
  • Test a Suspect Circuit Breaker.

Generator Testing
How to:

  • Test the Generator Charging Voltage.
  • Test the Voltage Drop Between: the Generator Output and the Battery Positive (+) Terminal.
  • Test the Voltage Drop Between: the Battery Negative (-) Terminal and the Generator Housing.
  • Test the Voltage Drop Between: The Generator Housing and the Block.
  • Test for Generator "AC Riding on DC."
  • Check For Bad Diodes in a Non Computer Controlled Generator using the “Diode Test Mode” of  the Digital Volt Ohm Meter.
  • Test for Shorted Diodes in the Generator Using the “Micro Amp Range” of the Digital Volt Ohm Meter.
  • Verify a Good Generator.
  • Test the Battery as a Possible Cause of Multiple Generator Replacements.

Relay Testing
How to:

  • Deal With a “Suspect Relay”.
  • Troubleshoot a Relay Controlled Circuit.

Starter Testing
How to:

  • Test the Cranking Voltage Available to the Starter Motor.
  • Test the Voltage Drop Between: the Battery (+) Terminal and the Starter Motor Armature Lead.
  • Test the Voltage Drop of a Starter Mounted or Remote Mounted Solenoid.
  • Test the Voltage Drop Between: Battery Negative (-) Terminal and the Starter Motor Housing.
  • Test the Voltage Drop Between: the Starter Housing and the Block.
  • Do a Starter Motor Amp Draw Test with a VAT 40 or 45.
  • Do a Starter Motor Amperage Draw Test With a Load Tester That Has a Voltmeter & Amp Meter, but No Inductive Pick Up.
  • Do a Starter Motor Amperage Draw Test With an Inductive Pick Up Plugged Into a Digital Voltmeter.

Shared Current Path and Voltage Drop Testing
How To:

  • Find Open Circuit, Charging, Or Source Voltage.
  • Find The Amount Of Source Voltage Available To Any Load.
  • Find The Voltage Drop Between: The Battery Positive Terminal And The Input Pin To Any Load.
  • Find The Voltage Drop Between: The Ground Side Of Any Load And The Battery Negative Terminal.
  • Find The Voltage Drop Between: Truck Bed And Cab Sheet Metal.
  • Find The Voltage Drop Between: The Battery Negative (-) Terminal And The Bulkhead Ground Strap.
  • Find The Voltage Drop Between: The Bulkhead And The Block.
  • Find the Voltage Drop Between: The Battery Negative (-) Terminal and A Battery Negative (-) Pigtail Attached To Sheet Or Frame Metal.

Other Tests and Information
How to:

  • Stop Electrical Switch Popping “Noise” in a Radio.
  • Find the Percent of Alcohol in Gasoline.
  • Check for Water in Brake Fluid Using a Voltage Drop Test.
  • Check Acid Content In Coolant With a Voltage Drop Test.
  • Test a Rear Window Defogger Using a Test Light.
  • Test a Rear Window Defogger using a Voltmeter.
  • Test Thermistor Temperature Sensors.

How a Voltage Drop Can Cause Ring Gear Damage.
Battery Drain Times When Components are Left On.
Wire Sizes, Diameter, Ohms/1000Ft. and Rated Continuous Amperage.
Observed wire sizes used on a 2007 C/K GMC.
How DC “Motor Drag” Can Affect Voltage Drop.
How DC Motor In-Rush Current Can Affect Voltage Drop.
Precautions to Observe Whenever a Vehicle Component is Unplugged.
When the Voltage Drop Is Still Excessive after Repair, Then What? ©