Electrical problems on Renault Trafic 1.9 dCi, causing various malfunctions.

In this video, we can see a Renault Trafic with a series of electrical problems that lead to various faults, not least the fact that the vehicle remains on even when the key is removed; the same problem occurs with the lights staying on. The problem is not solved even by disconnecting the ECU, the Body Control Unit, or the main relays.

The cause was identified by the YouTuber as a short circuit in the wiring: in fact, a bundle of cables rubs against a rod of the heating pipe, right above the gearbox.

The cables have been stripped, melting together. The video shows a classic case of lack of mechanical protection on the wiring, which is a very common design flaw in commercial vehicles.

A permanently live wire short-circuited with the ignition system cables. The solution is to inspect the wiring, following the path of the cable bundle above the gearbox, looking for wear, damaged insulation, or exposed wires.

Disconnect the battery and cut the damaged section with wire cutters, solder and connect the cables with heat shrink tubing, using insulating tape for protection. Rewind the wire bundle with heat-resistant ties and move the wiring away from the rod. Reconnect the battery and check that the engine turns off by turning the key, and the same happens with the lights.

In addition, we recommend checking the engine relay or fuel pump.