Another day as an auto electrician and another fault as a result of wear and tear. This Renault Megane came into us recently with a severe electrical fault causing the car to crank while parked up and nobody in it. As a French electrical specialist we see these vehicles pretty much on a daily basis and enjoyed another electrical challenge.
With the ignition not powering up there was not option to use the diagnostic computer this time. This was going to take proper diagnostic methods to find out the fault. Starting with the basics as we always do, we tested the various circuits connected to fault symptoms we had, and it wasn't long until we were led to the engine bay fusebox module.
After removing the cover we soon discovered we were looking at yet another water damaged car. This time not through the covers being incorrectly fitted but just through wear and tear causing the seal to the fusebox to perish and let water in. As you can see from the picture the water had made its way into the plugs and inside the module. We had no doubt straight away that this was the cause of the fault, but the unsettling thing with water ingress is you never know how far the damage may have travelled. Water shorting a circuit here can sometimes cause further module damage elsewhere.
Having informed the customer of what we had found so far, this module would have to be replaced before we could go any further. The wiring plugs were stripped down, cleaned and repaired and then a new module fitted and programmed. The car was now powering up as normal but due to the cranking issue the starter motor had burnt out. Another starter was ordered and fitted and the car was back up and running.
We put the vehicle on a long test to make sure no other faults were apparent before returning back to the customer for another successfully completed job.