Heavy Ranger® MUTT® (7-Way Round Pin)Mobile Universal Trailer Tester

The Heavy Ranger® MUTT® is a rugged, water-resistant trailer tester designed for commercial trailers with 7-way round pin connectors. It powers each trailer circuit—no truck required—to verify wiring configuration, ground integrity, short circuits, brake function, and turn signal operation.

Built for reliability in shop or yard environments, this standalone unit speeds up diagnostics, prevents blown fuses, and eliminates guesswork. The internal battery compartment offers cordless operation (battery not included), while the external 12V port adds flexibility—serving as a memory saver, test light supply, or trickle charger input.

Features and Benefits

Tests 7-way round pin trailer harnesses without connecting to a truck
Simulates turn signals, brake lights, and 12V power for system verification
Built-in short circuit and overload protection
Visual LED confirms power output at each circuit
Rugged, water-resistant design for field or shop use
Internal battery compartment (battery not in

Product Information