Car sounds alarm and lights flash

supersol

My car needed a battery recharge. When fixed to the charger, the car alarm starts sounding and the lights flash. This has not happened previously when charging. Can you help?

hartcjhart

Hi you may get more help if you say what car/model/year

supersol

Thanks. The car is a 2002 Lexus IS 200.

acerazor1

is the car unlocked with the ignition on when you charge it? Why do you need to charge the battery in the first place? If it keeps running flat then either your battery isnt holding cahrge, meaning a new battery show be bought, or your altenator isnt working properly. That or your leaving a light on

supersol

I left an inside light on overnight, which is why the battery needs charging. The ignition is off when I try to charge, but as soon as the plug on the charger is switched on, the alarm goes off.

acerazor1

supersol wrote: »

I left an inside light on overnight, which is why the battery needs charging. The ignition is off when I try to charge, but as soon as the plug on the charger is switched on, the alarm goes off.

The car thinks your stealing it. When a voltage is applied it dosent matter if the cars unlocked, you will need the ignition on to apply the voltage. Btw by ignition on i dont mean start the engine just turn the key till the dash lights are on then try turning on your charger.

supersol

Thanks - very helpful. I'm really grateful.

NickWarren_2

It's not something daft like the bonnet switch is it?

I can remember when i charged my mates Mitsi VR4, There is a little switch under the bonnet and when i reapplied the battery, the alarm went off as the switch wasnt depressed, and subsequently my head ended up hitting the bonnet hard lol