Hi everyone,

I was wondering if anyone has had a problem where the battery is dying at nighttime, but once I get it started, the alternator charges it up and it i restarts fine when turned off. Not sure what is going on, but it seems like maybe a light or radio is draining it. Is there an easy way to tell what it might be?

I've turned the lights out in the garage and nothing seems to be on. Also, just took it to the repair shop for brakes and this started happening straight after.

Thank you,

Chris
89 XJS Rouge Edition v12 5.3l

 

Chris,

If you have a battery drain, the easiest way to locate it is by pulling fuses. Here is the procedure.

Disconnect one terminal on the battery and connect a test light between the terminal and the battery.
If you have a short, the test light will be lit.
One by one, remove each fuse until the light goes out.
The fuse that that turns the test light off is the circuit that has the short.
Check that circuit on your fuse map and locate the short.

Be aware, that you may need to do this a couple of times as there may be more then one short and circuits that run the radio and the clock may be drawing a current all the time so eliminate those first.

Good luck.

 

The battery in my 92 model went dead several times, the first time at a mall at closing time. Took a while to figure it out.

The culprit was the right ventilation blower, which would not shut off without pulling the fuse. The sound of the engine fan running at shutdown covered it up, and because it was on the right side, I didn't notice it.

 

Thank you guys,
I think it must be something with a fan, but I'll check the fuses as described by alabbasi.

Hope it is something easy...

Thanks,
Chris
89 XJS Rouge Edition

 

My convertible had an alarm system and remote control door lock system that was after factory, but dealer added. The battery drain was high in that generation of alarm/door lock systems. Once removed the battery has been only taxed by the stereo radio system, and that has not produced any surprise non starts. Since I drive the car in nice weather times it has a C-tek system mounted to the battery and in the heat of Summer, and snowy days of winter it is an the trickle charger.