Base Bench Harness for ECM & TCM

Bench-testing ECMs and TCMs outside the vehicle is a critical step in heavy-duty engine conversions—catching wiring faults, calibration issues, or module failures early saves hours of troubleshooting after installation. Kustom Truck Parts' base bench harness serves as the reliable foundation for safe, accurate diagnostics on Caterpillar (ADEM2–ADEM4), Cummins (Celect–CM2350), Detroit Diesel (DDEC3–DDEC5), and similar electronics.  Reuse the base harness and replace ECM/TCM connector to match the engine you are testing.

Whether diagnosing engine issues during a repower, programming an engine's ECM, or confirming TCM function in an Allison swap, this base harness provides a consistent, professional starting point for all of your projects. 

Browse below for base bench harness options. Pair with our ECM/TCM jumper harnesses for full OEM testing. Need help selecting the right base harness or matching jumpers for your Caterpillar, Cummins, or Detroit project? Contact our team—we're here to assist with your conversion.