ELECTRICAL/ELECTRONIC SYSTEMS

For every task in Electrical/Electronic Systems, the following safety task must be strictly enforced:

Comply with personal and environmental safety practices associated with clothing; eye protection; hand tools; power equipment; proper ventilation; and the handling, storage, and disposal of chemicals/materials in accordance with federal, state, and local regulations.

The first task in Electrical/Electronic Systems is to listen to and verify the operator's concern, review past maintenance and repair documents, and determine necessary action.

VI. ELECTRICAL/ELECTRONIC SYSTEMS

A. General Electrical Systems Diagnosis

1. Read, interpret, and diagnose electrical/electronic circuits using wiring diagrams. P-1

2. Check continuity in electrical/electronic circuits using appropriate test equipment. P-1

3. Check applied voltages, circuit voltages, and voltage drops in electrical/electronic circuits using a digital multimeter (DMM). P-1

4. Check current flow in electrical/electronic circuits and components using a digital multimeter (DMM) or clamp-on ammeter. P-1

5. Check resistance in electrical/electronic circuits and components using a digital multimeter (DMM). P-1

6. Find shorts, grounds, and opens in electrical/electronic circuits. P-1

7. Diagnose parasitic (key-off) battery drain problems. P-1

8. Inspect and test fusible links, circuit breakers, relays, solenoids, and fuses; replace as needed. P-2

9. Inspect and test spike suppression diodes/resistors; replace as needed. P-3

VI. ELECTRICAL/ELECTRONIC SYSTEMS

B. Battery Diagnosis and Repair

1. Perform battery load test; determine needed action. P-1

2. Determine battery state of charge using an open circuit voltage test. P-2

3. Inspect, clean, and service battery; replace as needed. P-2

4. Inspect and clean battery boxes, mounts, and hold downs; repair or replace as needed. P-2

5. Charge battery using slow or fast charge method as appropriate. P-2

6. Inspect, test, and clean battery cables and connectors; repair or replace as needed. P-1

7. Jump start a vehicle using jumper cables and a booster battery or auxiliary power supply using proper safety procedures. P-2

VI. ELECTRICAL/ELECTRONIC SYSTEMS

C. Starting System Diagnosis and Repair

1. Perform starter current draw test; determine needed action. P-3

2. Perform starter circuit cranking voltage and voltage drop tests; determine needed action. P-1

3. Inspect, test, and replace components (key switch, push button and/or magnetic switch) and wires in the starter control circuit. P-2

4. Inspect, test, and replace starter relays and solenoids/switches. P-2

5. Remove and replace starter; inspect flywheel ring gear or flex plate. P-3

VI. ELECTRICAL/ELECTRONIC SYSTEMS

D. Charging System Diagnosis and Repair

1. Diagnose instrument panel mounted volt meters and/or indicator lamps that show a no charge, low charge, or overcharge condition; determine needed action. P-1

2. Diagnose the cause of a no charge, low charge, or overcharge condition; determine needed action. P-1

3. Inspect, adjust, and replace alternator drive belts, pulleys, fans, tensioners, and mounting brackets. P-1

4. Perform charging system voltage and amperage output test; determine needed action. P-1

5. Perform charging circuit voltage drop tests; determine needed action. P-1

6. Remove and replace alternator. P-3

7. Inspect, repair, or replace connectors and wires in the charging circuit. P-2

8. Diagnose AC voltage leakage (failed rectifier) at alternator output; determine needed action. P-2

VI. ELECTRICAL/ELECTRONIC SYSTEMS

E. Lighting Systems Diagnosis and Repair

1. Headlights, Daytime Running Lights, Parking, Clearance, Tail, Cab, and Instrument Panel Lights

1. Diagnose the cause of brighter than normal, intermittent, dim, or no headlight and daytime running light (DRL) operation. P-1

2. Test, aim, and replace headlights. P-2

3. Test headlight and dimmer circuit switches, relays, wires, terminals, connectors, sockets and control components; repair or replace as needed. P-2

4. Inspect and test switches, bulbs/LEDs, sockets, connectors, terminals, relays and wires of parking, clearance, and taillight circuits; repair or replace as needed. P-2

5. Inspect and test instrument panel light circuit switches, relays, bulbs, sockets, connectors, terminals, wires, and printed circuits/control modules; repair or replace as needed. P-2

6. Inspect and test interior cab light circuit switches, bulbs, sockets, connectors, terminals, and wires; repair or replace as needed. P-2

7. Inspect and test tractor-to-trailer multi-wire connector(s); repair or replace as needed. P-2

2. Stoplights, Turn Signals, Hazard Lights, and Back-up Lights

1. Inspect, test, and adjust stoplight circuit switches, bulbs/LEDs, sockets, connectors, terminals, and wires; repair or replace as needed. P-1

2. Inspect and test turn signal and hazard circuit flasher(s), switches, relays, bulbs/LEDs, sockets, connectors, terminals, and wires; repair or replace as needed. P-2

3. Inspect, test, and adjust backup lights and warning device circuit switches, bulbs/LEDs, sockets, horns, buzzers, connectors, terminals, and wires; repair or replace as needed. P-2

VI. ELECTRICAL/ELECTRONIC SYSTEMS

F. Gauges and Warning Devices Diagnosis and Repair

1. Interface with vehicle's on-board computer; perform diagnostic procedure using recommended electronic diagnostic equipment and tools (including PC based software and/or data scan tools); determine needed action. P-1

2. Diagnose the cause of intermittent, high, low, or no gauge readings; determine needed action. P-2

3. Diagnose the cause of data bus-driven gauge malfunctions; determine needed action. P-3

4. Inspect and test gauge circuit sending units, gauges, connectors, terminals, and wires; repair or replace as needed. P-2

5. Inspect and test warning devices (lights and audible) circuit sending units, bulbs/LEDs, sockets, connectors, wires, and printed circuits/control modules; repair or replace as needed. P-2

6. Inspect, test, replace, and calibrate (if applicable) electronic speedometer, odometer, and tachometer systems. P-2

VI. ELECTRICAL/ELECTRONIC SYSTEMS

G. Related Electrical Systems

1. Diagnose the cause of constant, intermittent, or no horn operation; determine needed action. P-2

2. Inspect and test horn circuit relays, horns, switches, connectors, and wires; repair or replace as needed. P-2

3. Diagnose the cause of constant, intermittent, or no wiper operation; diagnose the cause of wiper speed control and/or park problems; determine needed action. P-2

4. Inspect and test wiper motor, resistors, park switch, relays, switches, connectors, and wires; repair or replace as needed. P-2

5. Inspect wiper motor transmission linkage, arms, and blades; adjust or replace as needed. P-2

6. Inspect and test windshield washer motor or pump/relay assembly, switches, connectors, terminals, and wires; repair or replace as needed. P-3

7. Inspect and test sideview mirror motors, heater circuit grids, relays, switches, connectors, terminals, and wires; repair or replace as needed. P-3

8. Inspect and test heater and A/C electrical components including: A/C clutches, motors, resistors, relays, switches, connectors, terminals, and wires; repair or replace as needed. P-3

9. Inspect and test auxiliary power outlet, integral fuse, connectors, terminals, and wires; repair or replace as needed. P-3

10. Diagnose the cause of slow, intermittent, or no power side window operation; determine needed action. P-3

11. Inspect and test motors, switches, relays, connectors, terminals, and wires of power side window circuits; repair or replace as needed. P-3

12. Inspect block heaters; determine needed repairs. P-2

13. Inspect and test cruise control electrical components; repair or replace as needed. P-3

14. Inspect and test engine cooling fan electrical control components; repair or replace as needed. P-2