Electrical testing on vehicles is essential for diagnosing issues, ensuring proper function, and maintaining safety, particularly as modern vehicles increasingly rely on complex electrical systems. Electrical testing helps identify problems with components like the battery, alternator, wiring, sensors, and control modules. Below is an overview of some of the key electrical tests conducted on vehicles:

1. Battery Testing

The battery is one of the most critical electrical components in a vehicle. Testing ensures that it’s providing sufficient power for starting the engine and operating electrical systems. We use a Battery Conductance Tester which is currently the worlds most advanced conductance testing technology to easily, quickly and accurately measure the actual cold cranking amps capability of the vehicle starting battery, healthy state of the battery itself, and common fault of the vehicle starting system and charging system. Which can help Technicians to find their problem quickly and accurately, which achieves quick vehicle repairs.

2. Alternator Testing
The alternator charges the battery and powers electrical systems while the engine is running. A malfunctioning alternator can lead to electrical failures and poor battery performance.

• Voltage Output Test: The alternator’s voltage output is checked using an Oscilloscope or Multi-meter to ensure it’s charging the battery correctly.
• Ripple Test: This test checks for AC voltage being present in the DC output from the alternator. Excessive ripple may indicate issues with the alternator’s diodes or rectifier.
• Load Test: A load tester can simulate the electrical demands placed on the alternator to check if it can supply enough power to the vehicle’s electrical systems.

3. Fuses and Circuit Testing
Faulty fuses or circuit breakers can prevent electrical components from operating. Technicians will test for:

• Continuity Test: Using an Incandescent Test Light or Multimeter, technicians test fuses to ensure they’re not blown and that electricity is able to flow properly through the circuit.
• Circuit Voltage Test: This test checks the voltage at various points in the circuit to identify areas where power may be lost due to faulty wiring or connections.

4. Starter Motor Testing

The starter motor is responsible for cranking the engine when the ignition is turned. If it fails, the vehicle won’t start.

• Voltage Test: A voltage drop test checks for proper voltage delivery to the starter motor. If there’s too much resistance in the circuit, it may indicate a faulty connection or cable.
• Current Draw Test: A starter motor should draw a specific amount of current when engaging. Excessive draw may indicate internal damage to the starter.

5. Sensors and Control Modules Testing

Modern vehicles are packed with sensors and control modules that manage everything from engine performance to safety features. Testing these sensors ensures the proper functioning of the vehicle’s systems.

• Sensor Voltage Test: Many sensors, such as oxygen sensors or temperature sensors, require a specific voltage to operate correctly. A Multimeter can be used to measure sensor voltage and ensure it’s within the correct range.
• Signal Test: This test checks for the correct signal being sent to the vehicle’s control modules. For example, the throttle position sensor sends data to the engine control unit (ECU), and a failure could result in poor performance or engine codes.
• CAN Bus Testing: Vehicles with advanced electronics rely on the Controller Area Network (CAN) bus for communication between various control modules. A scan tool can be used to diagnose CAN bus issues, such as faulty wiring or communication errors. We also test all networks including LINBUS, KLINE and FlexRay.

6. Wiring and Grounding Tests

Faulty wiring or grounding issues can cause a variety of electrical problems, from intermittent failures to complete system breakdowns.

• Resistance Test: Using an Incandescent Test Light or multimeter, technicians measure the resistance in the vehicle’s wiring. High resistance can indicate corroded or damaged wires that could cause poor performance or power loss.
• Grounding Test: A bad ground connection can cause electrical faults or complete system failures. Technicians test the grounding points to ensure they’re secure and providing a good path to the vehicle’s chassis or battery negative terminal.

7. Lighting and Accessory Circuit Testing

Electrical testing also involves checking lighting circuits and accessories such as wipers, windows, and infotainment systems.

• Bulb Testing: Using an Incandescent Test Light or multimeter , technicians can ensure that power is reaching bulbs or LED lights, and that they’re operating at the correct brightness.
• Switch and Relay Testing: Testing switches, relays, and connectors ensures that components like headlights, fog lights, and indicators are operating correctly. A relay that is failing could prevent lights from functioning properly.

8. Diagnostic Scan (OBD-II)

Many modern vehicles are equipped with an On-Board Diagnostics (OBD-II) system or  an OBD Security Gateway that monitors the vehicle’s electrical and mechanical systems.

• Scan Tool Diagnostics: A scan tool connects to the OBD-II port and reads the vehicle’s computer for fault codes (DTCs). These codes can indicate electrical system faults, such as sensor failures or communication errors within control modules.

Safety Considerations in Electrical Testing

When performing electrical tests on vehicles, safety is paramount at AJ Fleetcare due to the potential risks associated with high-voltage systems, particularly in Electric Vehicles (EVs) and Hybrid vehicles. Technicians should always follow manufacturer safety guidelines, wear appropriate protective equipment (such as insulated gloves), and use tools rated for high-voltage testing when necessary. 

We book all electrical testing work with an initial 2hr testing charge. Any further testing will be discussed and authorised with/by the customer before any further testing is carried out.