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My F is showing its age, a 96 model that lives in the drive and has 78000 miles on the clock. Since a garage service and MOT I have experienced a problem with the battery discharging over a unused two day spell. The battery was replaced under guarentee two months ago.
Using the Circuit diagrams available on Dieter's web site I started fault finding on Power Distribution sheet 1 showing the under bonnet fusebox. The easiest suspect circuit was lights, powered by Link 1. With doors and boot shut and the bonnet lamp disconnected I isolated the battery positive. Using a 10 amp meter a reading of 0.7amps was recorded. The services powered by Fuses 2, 12 and 17 of the fusebox under the steering wheel removed and fuse 12 was the culprit. Refering to the diagram sheet 4 this fuse supplies 8 circuts inside the car. As all lamps were operating OK the fault was found in the Sony CD radio. After disconnecting the CD radio the current drain dropped to a pulseing (analogue clock) 30Ma.
Now my wife will use her car and I get mide back.
Hope this wordy input may help others.


Good bit of detective work PA.

I would have expected the CD radio to show a currect drain to maintain its memory.

Was it actually faulty?

Sam Murray

Hi Sam
The Sony model has a small reset button located under the head unit. After battery disconnection it is necessary to press and release the button. It looks like the button had been stuck in following the service work at the garage. By gently pressing the button with a soft plastic tube (from the WD 40) the reset action was heard to run and the load on the radio decreased to 8mA. The remaining battery drain is due to alarm and clock. After tuning the radio programmes all is OK including the CD player.
Regards Paul Liverton

This thread was discussed between 11/02/2009 and 14/02/2009

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