Hello,
I have been experiencing the dreaded cycling problem with my 2004 XK8. I press the key fob to unlock and it unlocks, locks, unlocks, etc 4 times before getting bored.
Extensive searching revealed the likely causes to be fuses or microswitches.
I have replaced both fuses (1 in the boot and one in the fascia) and the microswitches in both the door mechanisms.
Sadly, nothing has changed.
Where does that leave me? Is it a replacement electronics box?
Which one?
Any advice gratefully received.


Cheers,


John

 

Welcome John, I guess the first thing we ought to do is get you to the XK forum, this is the XJ, lets see if we can roust up a Mod. But in the meantime, I'm sure someone there will ask your battery condition. One thing both cars can suffer from is when the battery gets low, electrical gremlins come a crawlin'. Be sure to check your cables for any corrosion, if there is, replace it.

 

Oops!
Thanks for pointing that out!

I know the battery was replaced a couple of years ago. The cables look clean and tidy. I'm not sure how I can test it, beyond measuring the voltage while the engine is not running.

Cheers,


John

 

Check your ground points, especially the one in the trunk. Here's a link you'll want to put in your favorites.... JagRepair.com - Jaguar Repair Information Resource ...and be sure to review your Sticky's in the XK forum. Folks have put in a good effort there to make your life a little easier for many common repairs and TSB's.

 

Hi John,

I have moved your thread from the forum for the X308 XJ8 saloons to the forum for the X100, which is the Jaguar factory project code for your 2004 XK8. Here you will find knowledgeable owners of similar cars.

Cheers,

Don

 

A new battery solved the problem for me.


Stu

 

John +1 on battery. I've seen this many times, each time solved by an hour or two on the charger to top off the battery.

John

 

Thanks, everyone, for the useful suggestions.
Sadly, none of them has helped.
So far, I have replaced the microswitches in both door locks, replaced the fuse in the boot and the one in the dash and charged the battery for a whole day. I did check the microswitches operated correctly before I refitted the locks, too!
I suppose I could replace the battery anyway, but it's a lot of money if it doesn't help!
Are there any other avenues left to explore?


John

 

Hi John,

The computer modules in these cars are hard on the batteries. I had both the door lock cycling problem and the curse of the dropping window.

The battery started the car without a problem, but even on a trickle charger it would not hold enough of a charge to keep away the electrical gremlins.

A new battery was expensive, but it fixed the problems. I still keep it on the trickle charger if the car is going to sit for a week or more.


Stu

 

I know I'm clutching at straws, but:
Is there a similar microswitch in the boot/trunk lock, and could it be the problem, given that I have replaced both door microswitches?
I'll borrow a battery and try that, too, by the way...


Cheers,


John

 

Have you looked at "maintaining" your battery. Take a picture of any stickers, and look the battery up. If it is not AGM or "maintenance free", and you can confirm this is a conventional "low maintenance" acid-lead, you need to pop the covers off and top off the cells with distilled water. Typically gets you a fraction of a Volt, but could be enough of a boost, at least for a while.

Best of luck, keep us posted.