| Symptom | Likely circuit to check on diagram | |---------|-------------------------------------| | No crank, all dead | Battery cables, ignition switch (Pin 15 relay) | | Engine starts but no dash lights | CAN bus between EDC and cluster (wires CAN-H, CAN-L) | | One headlamp dead | Ground point behind headlamp (BR wire) or X4 connector | | Tachometer / speedo not working | Signal wire from transmission sensor (VDO) to cluster | | Intermittent wipers | Relay K10 (wiper interval) – often mislabeled on older diagrams |