www.jec.org.uk

hi everyone. i have a 1998 4.0L xk8. its been on every diagnostic machine known to man and reads normal for everything. however, it can still kill a good battery in 3 days. has anyone ever encountered a similar problem? and if so what the heck can be done about it apart from disconnecting the battery when its not in use for more than 2 days. all replies gratefully received

Hi, XK8 electrics are complicated so issues like this one may take a while to solve. Patience is a necessity when the diagnostics kit can't give an immediate answer. 3 days to empty a battery of juice is unusually quick and indicates a significant current flow. I assume that you've had a battery drop test carried out to ensure it's in good health; that you're using a battery of at least the Jaguar recommended capacity and you do not leave the keys in the ignition switch. Owners, (particularly just prior to a sale!) can be tempted to fit smaller, cheaper batteries but the hassle isn't worthwhile. The most obvious culprit is the boot light switch and/or its timer device. Failing that there are several circuits which remain live if the key is left in the ignition in the off position and for a period of time after it is removed. If you work through the fuse boxes methodically, removing fuses either one at a time or initially several together to identify the circuit or group of components responsible, you should be able to find the guilty circuit. Good luck. Mike.