Wiggle Test Protocol: A Systematic Approach to Locating Intermittent J1939 Harness Opens in Heavy Equipment

Technician performing systematic wiggle test on a J1939 Deutsch connector to locate an intermittent harness open in heavy equipment CAN bus

An intermittent J1939 open laughs at a bench multimeter. I’ve been on my back under a paving machine in the Texas heat, staring at a J1939 harness that looked fine, while the ECU logged CAN communication errors I couldn’t force to repeat. The operator said the transmission would drop into neutral for two seconds, only on rough ground. I’ve measured 0.2 Ω on a harness at rest that […]