09/13/2026
I have a c15 acert mxs model that I recently overhauled about a month ago, problem I'm having is the engine brakes quit working all the sudden, and can't figure out why, replaced all sensors, engine harness, and injector/jake, intake actuator harness, jake and intake actuator selenoids during the overhaul, and the jake switches on the dash are new. Truck has no codes. Do not have cat software, but I did use jpro to monitor the clutch switch, throttle pedal, jake switches, and watching the ecm command the Jake's on, all that looks good. Checked overhead, which was good. Updated quill studs that supply oil to the jakes, I'm getting nowhere here, any ideas? I don't see an engine brake fuse anywhere, I belive thats all supplied through the ecm through the ecm fuse.