The JLG 17400700 (Curtis 08137P) joystick controller is an industrial input module that translates operator stick movements into drive signals for aerial platform control systems. Common failure points include worn potentiometer tracks, damaged PCB traces from vibration or moisture ingress, and failing isolation relays that interrupt signal transmission to the main controller. Initial diagnostics should verify proper power supply voltage at the controller’s V+ and ground pins, inspect the joystick shaft and potentiometers for mechanical wear or debris, and check continuity across the signal output traces; reviewing any logged error codes from the host system can also pinpoint stuck or mis‑reported positions.[oss-gpt-20b]