car won't start!

[warrenh123]

Hello, I'm hoping someone here will be able to advise me on the best course of action.
I bought a '53 megane about 5 weeks ago and this morning it's packed in already ( just got rid of an old Mondeo i'd had for 5 years that never let me down LOL ).
The key card opened the doors as normal and the dashboard lit up ( don't know what it said ) but the car refused to start, the immobilizer light is now the only sign of life and the card no longer operates the doors. There is only one card so i can't check to see if another one will work.
Has anyone had any experience of this?
cheers, Warren.

[louiserd]

Battery?

[warrenh123]

Don't think it's the battery - I've tried a new one in the key card and the car battery should at least try to start.

[louiserd]

It doesn't really work like that on the Megane, due to the start button system. If you press the start button and everything just fails and sort of resets, it's the battery.

[warrenh123]

I think your right. I've just attached some jump leads ( just the red cable ) and everything came to life!
BTW yesterday the trip computer reset itself on start up which I thought was strange at the time, however it started ok with no indication that the battery was running flat. Maybe that was connected since the trip computer has reset itself again after starting up this morning.
Anyway thanks for the replys.

[AndyS]

If you only connected one cable (and the two cars weren't touching one another), then you didn't complete the electrical circuit and the other battery wasn't contributing anything. In this situation, if your problem disappeared (that is, the car started ok) then I'd strongly suspect a loose connection somewhere, which was (temporarily?) put right as you attached the jumper lead. Are the battery terminals clean?

Trip computer resetting itself when starting is a dead giveaway of a failing battery OR a loose connection in the main wiring / battery terminals.

[warrenh123]

Thanks for the reply Andy, I think you could be right. I thought it was strange that it started with only one jumper cable attached. On closer inspection the red lead on the battery was only finger tight ( you could actually wiggle the lead on the terminal ) although it didn't appear to be so loose that the connection would be broken i guess that's the prime suspect now.
Had it been my old car that would have been one of the first things i'd have checked. I suppose i don't trust these key cards etc and feared the worst instead of checking the basics.
Thanks again, Warren.

[AndyS]

The starter motor draws a LOT of current - even the slightest resistance in the circuit can cause problems. If any part of the cable termination/connection onto the battery can MOVE, then it's too loose! Having said this, don't overtighten it either as this can cause other problems. And be VERY careful with your tools when working on battery connections - an accidental short between the battery's positive (red) terminal and the car's engine or bodywork (which is connected to the negative terminal) can cause a nasty injury and/or expensive damage.