In early July I bought my BEAUTIFUL XK with under 26k on it. Just a weekend car, have a Prius as a beater so you can imagine my longing for the weekend. However 3 weeks ago with no red flags as I stopped to put gas in the Jag it wouldn't crank back up. All I hear is a single click. So for starts in mid July I put in a new DieHard AGM battery the previous battery had a slight drag in the start, Interstate Battery but I don't think it was a AGM which I've read are better batteries for Jags. Also when I purchased the car the previous owner already had a CTEK 4.3 for the car which I kept on thru the week. I'm kinda mechanically inclined so had it towed to my driveway for further inspection of what happened. Removed battery to have it tested which passed with flying colors. Tried mashing as hard as I could on the brake pedal still all I hear is a single click when pressing the start button. Replaced the battery in one of the key fobs as well still with no success. Replaced the starter which wasn't as hard as I thought especially doing it in the driveway, still the same problem. Press the start button, dash lights up normally with no strange lights all I hear is a single click so power is sounding like it's getting to the solenoid. Now 2 things I noticed is there is no power to starter fuse 30A Fuse is OK also switch around the relays. Also in another thread I now learned that the CTEK was hooked up wrong, it was hooked up directly to the negative post. Changed it to a ground to the body but still no crank. Hmm wonder if that caused damage for it not to crank. Looking For Some Help!!!

 

95% of the time it's ALWAYS the battery.

 

It's still charged up on the CTEK all the way up to the green light

 

That has nothing to do with it. Disconnect your battery from any charger, then let it sit for an hour or four. Check the voltage again. It should be 12.6 or higher. Turn on the headlights for a couple minutes then turn them off. Let it sit again for 20 minutes and check the voltage again..... should still be 12.6 or higher.

 

Okay I'll give it a try

 

What CeeJay said AND also about 3 years ago I had a bit of a fright, similar story, new battery so that wasn’t it. First thought was the starter and measured voltage at the starter and guess what, it was way too low. Checked wiring starting at the battery and it turned out somehow the main earth junctions, not on the battery but close by, had come loose.

Also I have had batteries which were fully functional one day go completely flat the next due to age.

 

UPDATE PROBLEM SOLVED!!! After several attempts to solve myself I came to the conclusion to take it to a Jaguar specialist shop. Fearing a huge repair bill but to my surprise it wasn't. The problem was something called a pass through bolt or terminal post . Its located between the back seat and battery. The plastic insulation on one end of the bolt was melted and it was grounding not getting enough current to the starter. $33.00 part $200 diagnosis and labor. Although now in the dead of winter Its still nice to go out and fire it up.

 

THANK YOU for closing this out with pertinent info for the fix!

 

All of us shade tree mechanics are stubborn meatheads who want to try to fix it ourselves before we give up and pay a pro to diagnose and fix it.

The Mo's experience is a good example of how it can actually cost less to have a pro fix it, particularly when you take your time and frustration into account.

But that's still not going to stop us from trying. You can't teach old dawgs new tricks!

 

Thought that said methheads. Mind is in the gutter.... must be Friday!

Glad to see a problem solved, nice job OP!

 

Plus a starter motor!
But you can sell it and get part of your money back.

 

[QUOTE=The Mo;2347497]UPDATE PROBLEM SOLVED!!! a pass through bolt or terminal post . Its located between the back seat and battery. The plastic insulation on one end of the bolt was melted and it was grounding not getting enough current to the starter. /QUOTE]
It would be great if you could post a picture or if not possible can you give any part numbers used in repairing it. Thanks.