My 2006 XK8 coupe has sat in my garage (in California) for months. I occasionally charged the battery (no I don't have a battery tender) but recently, after a charge, the car not only wouldn't start but acted as if the battery were dead flat. Voltmeter suggested that the battery was not taking a good enough charge (less than 12 volts) so I bought a new Interstate AGM battery and installed it. Nothing. Voltmeter shows nearly 13 volts at battery terminals but not even an interior light will come on, as if there were no battery installed at all.

I searched threads and found nothing helpful, only no-start problems. Have I somehow tripped an immobilizer? Even if that were so, I'd still see lights, etc., right?

Thanks in advance,

Granville

Let me just add that even when I was last driving the Jag regularly, it was showing what I figured were signs of a somewhat week battery, in that the passenger side window was not closing, upon closing the door, after lowering slightly when opening the door. By the time I had stopped driving it regularly, the driver's door was doing that as well. No other electric gremlins until now.

I would start with the possibility of dirty cable terminals not making good contact. Then I would follow the positive cable up to the HIGH voltage fuse connections and make sure of the voltage to ground on both sides of the fuses.

I was working in poor lighting and could not see that the negative terminal had a black plastic cap on it. No wonder I had to loosen the clamp so much to get it to push down onto the terminal all the way! Sorry folks. I really don't deserve a Jaguar...

I am just glad you found the solution.

LOL! Actually you admitted to your problem... isn’t that the first sign of recovery.

I think it’s a sign that you do deserve a Jag!

We’ve all had our “Homer Simpson” moment(s) Doh! Just glad yours was only a little one.

My “Goose” moments normally involve finding some important part/bolt left over when I’ve finished and started packing up. WTF! Then have to dismantle and start again.... Doh!

No worries. The good news is that you will never make that mistake again....

Now, go drive the car. These XK8s and XKRs need to be exercised regularly....