Megane 1996 electrical problem - Mike H
My son parked up our Megane for a few hours yesterday. When he came back to the car, he unlocked the car using the remote key fob. When he turned the ignition on, there was nothing - no lights on the dashboard and no reaction from the starter. He then tried to lock & unlock the car using the remote (which resets the immobiliser) - but when he unlocked it it only unlocked the front doors. The lights wouldn't work. He then called the RAC, but while waiting he tried it one more time and the engine started - but there were no warning lights alight on the dash after the ignition was turned on and before he started it. This morning, no problems, car behaved normally. Interestingly, when he used the car the other day, the radio asked for the code - which it should only do if the power had been interruped, so it had obviously suffered a power outage unnoticed.

Now, I would initially suspect a bad earth or break in the main power lead, but the symptoms seem to suggest something slightly more obscure. Any ideas out there?
Megane 1996 electrical problem - debugslife
Our Laguna done something sort of similar. My missus was using the car regularly and got me out of bed one morning to tell me the car wouldn,t start. She said she would turn the ignition key and the dials/lights went mental but the starter would not turn. I assumed she had flattened the battery despite her insistence that she had left nothing on. The central locking did not work at all. I opened the bonnet and brought our other car up to it and was about to attach jump leads. The weird thing was that as soon as I clamped the earth jump lead on to the battery terminal, I heard the central locking bursting into life. I hadn't connected the positive yet! I went ahead and hooked up the positive anyway and the car started as normal. It then ran fine and hasn't had a problem since. With hindsight I wish I had tried to start the car then and there without the jumpstart but she was desperate to get to work.

The point of all this boring story is that I suspect the connections on the earth post were poor and manhandling them was enough to clear the problem. Definitely worth taking them off and cleaning them up.
Megane 1996 electrical problem - Altea Ego
The clue is the radio code disapearing previously. This proves that full 12 volts + or negative return from a source near the battery is being lost. The standby circuit for the radio code(power all the time) does not go anywhere complex or fancy.

So Remove + clean both battery terminals & connectors. Trace where the negative terminals go to earth, remove clean and remake those. Trace your 12v to the main fuse and give those terminals a clean too. While you are in full terminal cleaning mode it wont hurt to remove and clean the engine/body earth strap.

 

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