Diagnostic Routine AM

Diagnostic Routine AM

Diagnostic Overview

The Trailer Battery Charging Is Inoperative Or Operates With The Ignition Off

Refer to Wiring Diagram Set 11 for schematic and connector information Electrical Diagrams.

Refer to Wiring Diagram Set 95 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Trailer Battery Charging .

Visual Inspection and Diagnostic Pre-checks

- Inspect the BJB (Battery Junction Box) fuses 93 (5A) and 24 (30A).

- Inspect the trailer tow connector for damage.

Pinpoint Test

NOTE: Before beginning diagnostics, visually inspect the trailer tow connector mounted on the bumper for signs of corrosion or damage. Repair or install a new trailer tow connector as required.

1. CHECK FOR VOLTAGE THROUGH THE TRAILER TOW CONNECTOR (BATTERY CHARGE INOPERATIVE)

1. Start the engine.

2. Measure:





Is the voltage greater than 11 volts?








2. CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR (BATTERY CHARGE ALWAYS ON)

1. Ignition OFF.

2. Measure:





Is any voltage present?








3. CHECK THE TRAILER TOW BATTERY CHARGE RELAY OUTPUT CIRCUIT FOR A SHORT TO VOLTAGE

1. Disconnect: Trailer Battery Charge Relay.

2. Measure:





Is any voltage present?








4. CHECK FOR VOLTAGE TO THE TRAILER BATTERY CHARGE RELAY COIL (ALWAYS ON)

1. Measure:





Is any voltage present?








5. CHECK FOR VOLTAGE AT THE TRAILER TOW CONNECTOR (BATTERY CHARGE INOPERATIVE)

1. Ignition OFF.

2. Disconnect: Trailer Tow Connector.

3. Start the engine.

4. Measure:





Is the voltage greater than 11 volts?








6. CHECK THE TRAILER TOW BATTERY CHARGE RELAY

1. Ignition OFF.

2. Disconnect: Trailer Tow Battery Charge Relay.

3. Substitute a known good relay.

4. Start the engine.

5. Measure:





Is the voltage greater than 11 volts?








7. CHECK THE TRAILER TOW BATTERY CHARGE RELAY VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the voltage greater than 11 volts?








8. CHECK THE TRAILER TOW BATTERY CHARGE RELAY COIL VOLTAGE SUPPLY CIRCUIT FOR AN OPEN

1. Ignition ON.

2. Measure:





Is the voltage greater than 11 volts?








9. CHECK THE BATTERY CHARGE RELAY COIL GROUND CIRCUIT FOR AN OPEN

1. Ignition OFF.

2. Measure:





Is the voltage greater than 11 volts?