2006 Renault Grande Scenic Electrical Problems
Symptoms and time line:
First faults were failure of rear window to come down on RHS and intermittent and erratic operation of the parking brake. Parking brake warning messages appearing on dash display while driving.
2 weeks later, the car could not be stopped by the ignition button. Car had to be stalled to stop the engine. Headlights were on full high beam, wipers were running at max, engine radiator fan running at full speed and RHS brake lights on. Turning off any relevant switches would not stop the functions. Battery had to be disconnected to turn off the above. On battery re-connect, every thing seemed normal, car started and ran normally. (except for parking brake fault and erratic park brake operation with beeping). Five minutes later, same happened again. Stall the engine. Wipers, headlights, engine fan all at max. Park brake fault with beeping. Disconnect battery again, but this time on reconnect, no dash display and car would not start. Relay clicking under passenger dash could be softly heard when trying to start, but no action. All fuses were checked on battery and in glove compartment, but all ok. Car could be locked and opened with the key, dash time display flashing and radio waiting for code on display. Interior lights were working.
Engine bay fuse panel was disassembled and checked to be all ok. Engine
card behind battery was checked, dry, and in good order. EPU? card under glove box was also dry and in good order. Computer diagnosis reported "No Communication" between modules.
Dampness noted on passenger side floor carpet. Signs of drips coming from foot well under dash.........!
Under the passenger seat is a major connection plug / socket arrangement in the main wiring loom of the car. Also here is another hidden fuse panel and relay. Check this area for moisture by removing the under seat glove compartment, and feeling the insulation in the area. If this shows any signs of dampness the seat has to be removed. In the "under seat area", the seat belt, carpet, plastic trim and airco ducts have to be removed to access the connector and fuse area. (see photos). In my case, the insulation here was totally soaked, and lots of water could be seen at the floor pan. The connector is poorly designed, being at the metal floor pan level, and then covered with felt insulation, entrapping water around the connector. The connector was severely corroded, and wires had broken away from there pins. A garage will charge you over ***8364;1000 to replace the wiring loom and connector! The alternative is this :
Clean up the connector with Methylated Spirits ( not White Spirit!) and a brush. Metho will absorb water and remove the "vertigres" and dry it out. Apply liberally. In my case, 9 wires had broken away from the socket. The process in involves locating where each wire in the socket was and cutting the wire on the good side of the socket, and connecting the wires externally from the socket (see photos). Pull each wire in the socket to make sure it is connected, as the decay of copper can be hidden by the insulation, leaving intermittent and failing connections. Use a connector block to make the new connections. Be warned that sometimes the colours do not match on either side of the plug socket arrangement. Do it by position in the plug. Do the colours that match first. Once each wire is done attempt to start the car to test. Once done and clean, apply a liberal amount of WD40 and Vaseline to the new connector block and existing plug/socket arrangement, and cable tie the connectors higher up off the floor, on a the metal strut.(see photos) This area will remain damp for a long time, and this prevents the fault from re occurring immediately. Remove and discard insulation around the area. Punch holes through the floor pan to allow water to drain away (see photos). Once done, check operation of all functions. Start the car. Reset the windows by holding the up button for 10 seconds on each window with the window at the top position. Reset the handbrake by manually applying/releasing the handbrake 5 times with the engine running. Check headlights, brake lights etc. Once happy, reassemble the whole seat area with the reverse of the disassembly.
The cause of this water and faults, is blocked drain pipes , either side, below the window in the engine bay. This is a common fault with modern cars in high humidity countries. The water is meant to be drained away from this area into the wheel arch area. In my case the water was over 20mm deep sloshing around in the whole panel. (see photos). See this link here to repair this issue : https://www.youtube.com/watch?v=mVNStlZLqts
These should be maintained every 6 months in the Uk and Ireland evnviroments.