12V Automotive Relay Tester – 4 & 5 Pin

Check compatible 4-pin and 5-pin automotive relays with this compact 12V relay tester. Its battery leads, pin selector and TEST button provide a straightforward pass/fail check of relay switching, with a red/green LED indicator.

Compatibility and specifications

• Model identified in the supplier instructions: CNBJ-707.
• Power source: 12V vehicle battery within an 11–15V range.
• For common automotive relay pin layouts that match the tester's sockets; not compatible with every relay.
• Supplier recommends relay coil resistance above 20 ohms.
• Three relay receptacles and a 4PIN/5PIN selector.
• Approximate body dimensions: 11 × 6 × 4.06 cm.
• Supplier-listed cable length: approximately 88 cm.

How the test works

Follow the tester and vehicle manufacturer's instructions. Connect the black clip to the battery's negative terminal and the red clip to its positive terminal. The red LED indicates power-up readiness before a test.

Check the relay's pin layout, choose 4PIN or 5PIN, then insert it into the matching socket and press TEST. For a compatible layout, the tester cycles the relay ten times to check contact opening, closing and consistency.

After testing: green indicates a pass; red indicates a failed test or an incompatible/damaged pin configuration. A red result alone does not establish which fault is present. Disconnect the battery leads and remove the relay when finished.

Important: this is a relay tester, not a general-purpose circuit or battery diagnostic tool. Use only within the specified supply range, not on a 24V system. Keep clips from touching each other and follow appropriate vehicle-battery precautions. If unsure about relay compatibility or battery connections, ask a qualified automotive technician.

What's included

One relay tester with attached battery leads and clips. Battery, vehicle and example relays shown are not included.