Aermotor EM285 Automotive Electric Circuit Tester

1. Introduction

The Aermotor EM285 Automotive Electric Circuit Tester is a versatile tool designed for diagnosing electrical systems in vehicles. It operates on 6-24V DC systems and offers a wide range of applications, making it an essential tool for automotive technicians and DIY enthusiasts. This manual provides detailed instructions on how to safely and effectively use your circuit tester.

2. Safety Information

• Always wear appropriate eye protection when working on vehicle electrical systems.
• Ensure the vehicle's ignition is off before connecting or disconnecting the tester, unless specific tests require power.
• Do NOT use this device on AC voltage. It is designed exclusively for 6-24V DC automotive systems.
• Avoid touching live electrical components with bare hands.
• Keep the tester and its cables away from moving engine parts, hot surfaces, and sharp edges.
• The unit has 8A overload protection. If the current exceeds 8A, the device will automatically disconnect the current to prevent damage.

3. Package Contents

Your Aermotor EM285 Automotive Electric Circuit Tester package should include:

• 1 x Aermotor EM285 Circuit Tester with integrated cable and alligator clips

Please inspect all items for any damage or missing parts upon unboxing.

4. Product Overview

The Aermotor EM285 Circuit Tester consists of a main unit with a probe tip, a long cable, and two alligator clips for connecting to the vehicle's battery. The main unit features LED indicators for positive and negative voltage, and a rocker switch to apply power to the probe tip.

Figure 4.1: Aermotor EM285 Circuit Tester components.

Figure 4.2: Close-up of the tester's positive/negative LEDs and rocker switch.

5. Specifications

6. Setup

To prepare your Aermotor EM285 Circuit Tester for use:

1. Unroll the unit's cable completely to avoid tangles and ensure maximum reach.
2. Clamp the red alligator clip securely to the positive terminal of the vehicle's battery.
3. Clamp the black alligator clip securely to the negative terminal of the vehicle's battery.

Once connected, the tester is ready for operation. The LEDs on the unit will indicate the presence of power.

7. Operation

The Aermotor EM285 Circuit Tester can perform various diagnostic functions:

7.1. Testing for Voltage and Polarity

• Touch the probe tip to the circuit or component you wish to test.
• The LED indicators on the tester will light up:
• Red LED (POSITIVE): Indicates a positive voltage.
• Green LED (NEGATIVE): Indicates a negative voltage (ground).
• If neither LED lights up, there is no voltage present or the circuit is open.

7.2. Testing Continuity

• Ensure the circuit or component is de-energized before testing continuity.
• Connect the auxiliary ground clip (small black clip) to a known good ground.
• Touch the probe tip to one end of the component or wire you want to test.
• If the green LED lights up, there is continuity to ground.
• Alternatively, you can apply power to the probe tip (see 7.3) and touch the other end of the component to a known ground. If the component functions (e.g., a light bulb lights up), continuity is confirmed.

7.3. Applying Positive or Negative Battery Current

This feature allows you to power up components or test circuits directly.

• Touch the probe tip to the component or circuit you want to power.
• To apply positive battery current, rock the power switch forward (towards 'POSITIVE'). The red LED will light up, and positive voltage will be sent to the probe tip.
• To apply negative battery current (ground), rock the power switch backward (towards 'NEGATIVE'). The green LED will light up, and ground will be sent to the probe tip.
• Release the switch to stop applying current.
• Use this function to check lamps, electric motors, switches, relays, and the on-off status of diodes, fuses, and circuits.

7.4. Tracking and Locating Short Circuits

• The tester can help locate short circuits by applying power to a suspected circuit and observing where the overload protection trips or where the circuit fails.
• When the 8A overload protection trips, it indicates a short circuit or excessive current draw.

7.5. Testing for Bad Ground Contacts

• Connect the main alligator clips to the battery.
• Touch the probe tip to the suspected ground point.
• If the green LED does not light up, or lights up dimly, the ground connection may be poor or absent.

Figure 7.1: Testing a fuse box with the circuit tester.

Figure 7.2: Visual guide to the tester's applications.

Figure 7.3: Demonstrating continuity test with a light bulb.

8. Troubleshooting

• Tester not powering on: Ensure the red and black alligator clips are securely connected to the correct battery terminals (red to positive, black to negative) and that the battery has sufficient charge.
• No LED indication: If probing a circuit and neither LED lights up, verify the circuit is powered and that there isn't an open circuit. For continuity tests, ensure a good ground connection.
• Tester automatically shuts off: The device has an 8A overload protection. If it shuts off, it indicates that the current drawn by the circuit or component being tested exceeds 8A, likely due to a short circuit or a component drawing too much power. Disconnect immediately and investigate the circuit for faults.
• Inaccurate readings: Ensure all connections are clean and tight. Corroded terminals or loose connections can lead to false readings.

9. Maintenance

• After each use, clean the probe tip and alligator clips with a dry cloth to remove any dirt or residue.
• Store the tester in a dry, cool place, away from direct sunlight and extreme temperatures.
• Keep the cable neatly coiled to prevent damage.
• Do not attempt to disassemble or repair the unit yourself. Refer to the warranty and support section for service.

10. User Tips

• Understanding the small clip: The small black clip is typically an auxiliary ground. It's useful for continuity testing where you need to establish a direct ground reference for the probe tip, especially when the main battery ground is inconvenient or you're testing a component's ground path.
• Testing fuses: You can quickly check fuses by touching the probe tip to both test points on top of the fuse. If both sides show voltage (red LED), the fuse is good. If only one side shows voltage, the fuse is blown.
• Cable management: The 16ft cable is very convenient for reaching various parts of a vehicle. Take advantage of its length but ensure it's not draped over hot engine parts or sharp edges during use.

11. Warranty and Support

For any questions, technical assistance, or warranty claims, please contact the seller, PRO OBD2 Tool Store. They offer a 24/7 online guide for customers. If you do not receive an immediate response, please leave a message via trademageman or email, and they will respond as soon as possible.

If the item is broken in transportation or does not work, please send it back for repair or exchange.