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Theory Of Operation

GC0157765Courtesy of CHRYSLER GROUP, LLC

The purpose of the following procedure is to demonstrate different methods of checking for a short to voltage in a circuit. When diagnosing a DTC it might be necessary to verify that proper voltage is on a circuit or that a circuit is not shorted high.

NOTE:

The circuit shown in illustration is an example, and is intended for demonstrational purpose only.

The following are circuit tests covered in this procedure:

NOTE:

Perform the following test using a known good test light or functioning multimeter.

Below is a list of possible causes that could be related to a Short To Voltage condition.

Possible Causes
SHORTED CIRCUIT (CHAFED, PIERCED OR PINCHED WIRES)
SHORTED IN-LINE CONNECTOR (BENT, PUSHED OUT OR CORRODED TERMINALS)
  1. TESTING FOR A SHORT TO BATTERY VOLTAGE USING A TEST LIGHT 
    GC0157946Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    Before testing any circuits, first verify the 12-volt test light is operating properly. Connect the 12-volt test light to battery ground or to any other known good ground. Touch the lead of the test light to Battery(+). If the test light is operational, it should illuminate brightly.

    1. Turn the ignition off.
    2. Disconnect the wire harness connectors of all components that contain the circuits that are suspected of having the short.
      NOTE:

      Check connectors - Clean/repair as necessary.

    3. At this time leave all in-line connectors connected.
    4. Connect the 12-volt test light to a known good ground.
    5. Use the lead of the test light and carefully probe the circuit suspected of having the short.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    6. First, check with the ignition off, next with the ignition on, and lastly while cranking the engine.

      Does the test light illuminate brightly?

      Yes 

      • Repair the short to voltage. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur.
      • One method to help isolate the short is to disconnect any in-line connectors that the circuit being checked runs through and check for the short again. If the short goes away, the short is on the other side of the in-line connector.

      No 

      • The circuit is not shorted to voltage or the condition that originally caused the short may not be present at this time. Continue to measure the resistance and wiggle the wire harness to check for an intermittent short.
        NOTE:

        By disconnecting the wire harness connectors you may have eliminated the source of the voltage causing the short. Use the wiring diagram as a guide, check to see if there are any battery circuits in the same wire harness as the circuit you are testing. It is necessary to check for a short to those circuits using an ohmmeter. Perform the Check for a Short Between Multiple Circuits diagnostic procedure.

      • Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur intermittently.
      • Look for any chafed, pierced, pinched, or partially broken wires.
      • Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related component and wire harness connectors.
      • Perform any Technical Service Bulletins (TSBs) that may apply.
  2. TESTING FOR A SHORT TO SWITCHED IGNITION VOLTAGE USING A TEST LIGHT 
    GC0157625Courtesy of CHRYSLER GROUP, LLC
    NOTE:

    Before testing any circuits, first verify the 12-volt test light is operating properly. Connect the 12-volt test light to battery ground or to any other known good ground. Touch the lead of the test light to Battery(+). If the test light is operational, it should illuminate brightly.

    1. Turn the ignition off.
    2. Disconnect the wire harness connectors of all components that contain the circuits that are suspected of having the short.
      NOTE:

      Check connectors - Clean/repair as necessary.

    3. At this time leave all in-line connectors connected.
    4. Connect the 12-volt test light to a known good ground.
    5. Use the lead of the test light and carefully probe the circuit suspected of having the short.
      WARNING:

      When the engine is operating, do not stand in direct line with the fan. Do not put your hands near the pulleys, belts or fan. Do not wear loose clothing. Failure to follow these instructions may result in possible serious or fatal injury.

    6. First, check with the ignition off, next with the ignition on, and lastly while cranking the engine.

      Does the test light illuminate brightly?

      Yes 

      • Repair the short to voltage. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur.
      • One method to help isolate the short is to disconnect any in-line connectors that the circuit being checked runs through and check for the short again. If the short goes away, the short is on the other side of the in-line connector.

      No 

      • The circuit is not shorted to voltage or the condition that originally caused the short may not be present at this time. Continue to measure the resistance and wiggle the wire harness to check for an intermittent short.
        NOTE:

        By disconnecting the wire harness connectors you may have eliminated the source of the voltage causing the short. Use the wiring diagram as a guide, check to see if there are any battery circuits in the same wire harness as the circuit you are testing. It is necessary to check for a short to those circuits using an ohmmeter. Perform the Check for a Short Between Multiple Circuits diagnostic procedure.

      • Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur intermittently.
      • Look for any chafed, pierced, pinched, or partially broken wires.
      • Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related component and wire harness connectors.
      • Perform any Technical Service Bulletins (TSBs) that may apply.
  3. TESTING FOR A SHORT TO BATTERY VOLTAGE USING A VOLTMETER 
    GC0157617Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the wire harness connectors of the components that contain the circuit that is suspected as having a short.
      NOTE:

      Check connectors - Clean/repair as necessary.

    3. At this time leave all in-line connectors connected.
    4. With all the component wire harness connectors disconnected, use a multimeter set to measure DC voltage.
    5. Connect the ground lead of the meter to a known good ground.
    6. Use the positive lead of the multimeter and probe the circuit that is being checked for a short.

      Is there any voltage present?

      Yes 

      • Repair the short to battery voltage. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur.
      • One method to help isolate the short is to disconnect any in-line connectors that the circuit being checked runs through and measure for the short again. If the short goes away, the short is on the other side of the in-line connector.

      No 

      • The circuit is not shorted to voltage or the condition that originally caused the short may not be present at this time. Continue to measure the voltage and wiggle the wire harness to check for an intermittent short.
        NOTE:

        By disconnecting the wire harness connectors you may have eliminated the source of the voltage causing the short. Use the wiring diagram as a guide, check to see if there are any battery circuits in the same wire harness as the circuit you are testing. It is necessary to check for a short to those circuits using an ohmmeter. Perform the Check for a Short Between Multiple Circuits diagnostic procedure.

      • Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur intermittently.
      • Look for any chafed, pierced, pinched, or partially broken wires.
      • Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related wire harness connectors.
      • Perform any Technical Service Bulletins (TSBs) that may apply.
  4. TESTING FOR A SHORT TO SWITCHED IGNITION VOLTAGE USING A VOLTMETER 
    GC0157790Courtesy of CHRYSLER GROUP, LLC
    1. Turn the ignition off.
    2. Disconnect the wire harness connectors of all components that contain the circuits that are suspected as being shorted.
      NOTE:

      Check connectors - Clean/repair as necessary.

    3. At this time leave all in-line connectors connected.
    4. With all the component wire harness connectors disconnected, use a multimeter set to measure DC voltage.
    5. Connect the ground lead of the meter to a known good ground.
    6. Use the positive lead of the multimeter and probe the circuit suspected of having the short.
    7. Ignition on, engine not running.

      Is any voltage present?

      Yes 

      • Repair the short to ignition voltage. Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur.
      • One method to help isolate the short is to disconnect any in-line connectors that the circuit being checked runs through and check for the short again. If the short goes away, the short is on the other side of the in-line connector.

      No 

      • The circuit is not shorted to voltage or the condition that originally caused the short may not be present at this time. Continue to measure the voltage and wiggle the wire harness to check for an intermittent short.
        NOTE:

        By disconnecting the wire harness connectors you may have eliminated the source of the voltage causing the short. Use the wiring diagram as a guide, check to see if there are any battery circuits in the same wire harness as the circuit you are testing. It is necessary to check for a short to those circuits using an ohmmeter. Perform the Check for a Short Between Multiple Circuits diagnostic procedure.

      • Use the wiring diagram as a guide to trace the circuits and look for any in-line connectors where the short could occur intermittently.
      • Look for any chafed, pierced, pinched, or partially broken wires.
      • Look for broken, bent, pushed out or corroded terminals. Verify that there is good pin to terminal contact in the related wire harness connectors.
      • Perform any Technical Service Bulletins (TSBs) that may apply.
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