Match the part number, measurements and connection points that apply to your trailer.
| Connector | Match the connector and circuit count. |
|---|---|
| Function | Verify circuits rather than wire color alone. |
| Voltage | Confirm system voltage. |
This tester checks both 7-way RV blade connectors and 4-flat trailer plugs to confirm that power is reaching the trailer connector on your tow vehicle. It quickly verifies that the vehicle wiring and trailer fuse circuits are functioning before you connect your trailer.
Modern trucks often use dedicated fuse circuits for trailer wiring. When a fuse blows or wiring fails, the issue is not always obvious. This tester confirms that power is present at the plug so you can identify wiring problems before hitting the road.
Need help identifying trailer wire colors? Click here for a wiring reference guide.
Trailer wiring problems are commonly caused by blown vehicle fuse circuits, damaged connectors, or corroded trailer plugs. Testing the tow vehicle connector before connecting the trailer helps isolate whether the problem is in the vehicle wiring or the trailer wiring.
Wire colors are not always reliable across different trailer manufacturers, so electrical testing should always be used to confirm the function of each circuit.
Verify wiring functions before connecting your trailer.
