I have a problem with my 2005 XK8. If it's a short, it's unlike any I have ever seen. By the way, this my first jag, and I'll never go back!

What happens is, the car goes (almost) completely dead. Nothing works, but the red idiot lights in the oil pressure gauge and the ammeter stay on whether the switch is on or off, or even if the key is out of the switch. The failure occurs at random times. Sometimes it happens as soon as I turn the switch on. At other times, everything comes on normally, but it dies as soon as I engage the starter. Or the car will unlock normally with the fob, but be dead as soon as I turn the switch on. It even happened once while I was driving the car.

It is simple to fix. All I have to do is disconnect and reconnect the positive battery cable. Actually, usually just loosening and jiggling the connector fixes it. I tried cleaning the connectors, but it doesn't seem to have helped. It also seems to happen in spurts. It will go several days or a week or two without a problem, then happen three or four times in the same day.

Having said all of that, I have to admit that automotive electrics is far from my area of expertise. If I need to take it to a specialist, I will. I would just hate to spend $1000 on something simple that I could fix myself.

Any suggestions?

Thanks, Rob

 

Hi Rob,
Start with checking the age of the battery and state of charge.

Then check the ground points in the trunk and engine bay. This is the easiest and cheapest thing to do and you need a good known starting point.

 

Hi.


Assuming your battery poles are clean and tight, the next I would check are the connections to the megafuses in the front of the trunk. (Where the positive cable ends up.)
The positive cable from the battery has been known to go bad. It looks ok, but has detoriated inside. This would be possible in your case reading your description of fixing the problem. Some members have fixed it by tightening the clamps on the cable. Better to change it.


It's always a good idea to disconnect battery while working on the electrics

 

Install a new AGM battery and give it a slow charge over night no matter what the battery shop tells you, "our batteries are fully charged". Be sure to reset the windows after disconnecting the battery. Full down and hold the button until you hear a click, Full up and hold the button until you hear a click.

Good luck with your next car!

 

do a quick search and check grounds while your at it, there was a very recent post which a member thankfully attached the grounding points.
https://www.jaguarforums.com/forum/x...roblem-127619/