Aermotor 12V 24V Car Relay Tester – Auto Diagnostic Tool

Stop Guessing — Know Exactly If Your Car Relay Is Working

The Aermotor 12V/24V Automotive Relay Tester is the compact, easy-to-use diagnostic tool every driver and mechanic needs in their kit. Whether your car lights are flickering, your wipers are acting up, or your starter is misbehaving, a faulty relay is often the culprit — and this tool lets you pinpoint the problem in seconds. Compatible with both 4-pin and 5-pin relays used in most cars, trucks, and SUVs, it connects directly to your vehicle's battery for instant, accurate results.

Made in Mainland China.

Why Relay Testing Matters

Automotive relays control nearly every major electrical system in your vehicle — headlights, wipers, starters, air conditioning, power windows, electric seats, anti-lock brakes, and audio systems. Exposure to vibration, extreme heat, cold, and humidity gradually degrades these relays over time. When a relay fails, it can cause an entire system to stop working — or worse, leave you stranded. Regular relay checks with a dedicated tester can prevent costly breakdowns before they happen. Learn more about automotive electrical safety at the U.S. Consumer Product Safety Commission (CPSC).

Key Features

• Universal 12V & 24V Compatibility: Works with standard automotive batteries (11V–15V range) for both passenger vehicles and light commercial vehicles.
• 4-Pin & 5-Pin Relay Support: Three onboard receptacles and a pin-selector switch accommodate the most common relay configurations.
• LED Pass/Fail Indicator: Clear green LED for a passing relay; immediate red LED alert for a faulty or misconfigured relay — no guesswork required.
• 10-Cycle Contact Test: Automatically opens and closes the relay 10 times to measure contact closure time, opening time, and consistency.
• Checks Pin Configuration: Instantly identifies if the relay's pin layout matches standard automotive specs.
• CE Certified: Tested and certified for safety and performance.
• Compact & Portable: Dimensions of just 13 × 7 × 3 cm — fits easily in your glove box or tool bag.
• No Batteries Required: Powered directly from your car battery via included alligator clip leads.

How to Use the Relay Tester — Step by Step

1. Clip the black alligator lead to your battery's negative terminal and the red lead to the positive terminal. The red LED will illuminate to confirm power.
2. Inspect your relay — identify whether it is a 4-pin or 5-pin type and set the selector on the tester accordingly.
3. Insert the relay into one of the three receptacle sockets on the tester.
4. Press the TEST button.
5. The tester verifies pin configuration first. If the relay is non-standard or a pin is damaged, the red LED lights immediately.
6. If the pin check passes, the tester cycles the relay open and closed 10 times, measuring contact timing. A timeout triggers the red LED.
7. After all 10 cycles, the tester checks contact consistency — green LED = pass, red LED = fail.
8. Disconnect the alligator clips from the battery and remove the relay.

Specifications

• Brand: Aermotor
• Voltage Range: 12V – 24V (11V–15V operational)
• Supported Relay Types: 4-pin, 5-pin automotive relays
• Dimensions: 13 × 7 × 3 cm
• Certification: CE
• Power Source: Vehicle battery (no batteries included or required)
• Origin: Mainland China

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Frequently Asked Questions

Q: What types of automotive relays does this car relay tester support?

A: The Aermotor relay tester supports the most common 4-pin and 5-pin automotive relays used in cars, trucks, and SUVs. It features three relay receptacle sockets and a pin-selector switch so you can easily test different relay configurations without adapters.

Q: Do I need a separate power source or batteries to use this relay tester?

A: No additional batteries are required. The tester is powered directly by your vehicle's 12V or 24V battery using the included alligator clip leads (red to positive, black to negative). The red LED confirms when the unit is powered up and ready to test.

Q: How does the tester tell me if a relay has passed or failed?

A: The tester uses a simple color-coded LED system: a green LED means the relay passed all checks (pin configuration, contact timing, and consistency), while a red LED means the relay is faulty, misconfigured, or has a damaged pin. Results are displayed after the automated 10-cycle contact test.

Q: Can this tool also test an alternator or car battery condition?

A: This tool is specifically designed as an automotive relay tester and relay contact diagnostic tool. While it connects to the vehicle battery to power the relay coil during testing, it is not a dedicated alternator load tester or battery health analyzer — it is optimized to accurately diagnose relay function and contact performance.