www.jec.org.uk

Hi - I hope someone has been here before and recognises the symptoms!

My central locking (XKR, MY2001) started to play up about a month ago, in that when unlocking from the remote, the drivers door "lock motor" would bounce, in that it would lock, unlock, lock, unlock etc until you opened up the door... then it would be fine. The doors would lock as usual when you drive off.

Today... it bounced the locks for a while, and then will not lock with the central locking at all...meaning I had to manually lock the passenger door from inside and use the key for the drivers door.

The remote fob is working as the alarm is still responding.

I am assuming there is a mode switch in the drivers door lock area... can anyone confirm if this is a likley culprit and if its a std microswitch or part of a larger (expensive no doubt) assembly?


Many thanks

David

Recognise the symptoms just wish I knew what caused it. Mine started playing up after heavy rain set the alarm off. A few days earlier I had had the car washed with a jet wash. So I think water ingression had a part to play in my locks bouncing uncontrollably. My local jag specialist didn't necessarily agree and reckoned the latches had become defective. Both were replaced and when I collected the car the bouncing lock problem had gone but only the following day I notice that the passenger door window was not dropping when the door was opened. I and others tried to reset the windows but failed. After a week back in the garage the window problem was cured. I still think water had a part to play in my situation because the car had been fine for 18 months from purchase and a) the jet wash was the first and only time I've used a jet was on the car and b) the rain was heavy and non stop all night.

Thanks for the reply...

I think I am getting closer and suspect its the door latch microswitch... I need to check again and swap it.

After a battery reset its been ok... ish...only playing up twice in two weeks.

I will keep you posted.

David

Hello,

I am having a frustrating time with my door locks too...any advice much appreciated. Three visits to my local independent garage & £300 down & still not fixed So far we have had new passenger door latch, a replacement ECU and a wiring fault behind the dash corrected.

It is an intermittant fault. I am certain it comes with damp weather. Perhaps a coincidence, but my problems began after I got home from driving through a Lake District deluge (2-3 inches of flood water on the road & battering down with rain). The problems come back if the weather is damp & vanish as it dries up. But my jag garage insist this is impossible & water can't affect anything. What do you experts think?

It is a 2002 4.0 litre with c.57,000 miles. It lives on the driveway in not-so-sunny Cheshire.

Problem:
1. Sometimes the door locks will "bounce" - similar to Dave's problem. Mostly when I come to lock or unlock the car, as if it is confused and can't decide whether it is in a locked or unlocked state. Usually it bounces 3-6 times & then the alarm goes off (which is embarassing at 6am!).

2. On three seperate occasions the door locks have both begun "bouncing" as I put it into Drive gear & set off up the road.

3. Sometimes I will attempt to lock the car & there is no "clunk" of any door locking, but the lights (hazards, indicator etc) will flash once. If I press the keyfob "lock" button a 2nd time (which sets the alarm), then the alarm sounds. I am told that the alarm is sounding because the ECU thinks an exit is still open.

4. We had a phase when the car (intermittantly) couldn't be locked with either key fob and I had to manually operate the key in the drivers door (to be fair, this problem hasn't come back since we had a new ECU "security brain" put in).

I have lost faith in my usually very good indepedent jag garage & don't know what to do next. I also find it very frustrating that they keep dismissing the fact it could be water-related (each time I mention it they look at me like I am mad).

I think the next thing to try would be a new driver's side door latch, but I'm reluctant to spend another £120 on top of the £300 already gone, for that to turn out not to have been the problem either.

The garage have had the diagnostics box on it several times & the only error message ever seen was just one "passenger door not locked" (which I think might have caused myself by opening the passenger door lock from the inside when the ECU was playing up).

Any suggestions much apprecriated!

Thanks,
Lisa

Hi Lisa,
The symptoms you describe do sound like a faulty door latch microswitch. Jaguar started supplying these switches separately from the complete door latch assemblies (much cheaper) and I'm not aware that situation has changed. Of course, it's possible that dampness affecting an earthing point for the latches could induce similar problems. Hence, the simplest first step would be to clean all earthing points and use geneous quantities of W40 or a similar protective material. However, the latch microswitch remains the most likely culprit. Mike.

Thanks Mike.

Lisa

An update for the forum - the saga of the central locking problems on my 2002 XK8 is finally resolved. Hopefully this post can save somebody the hasssle & expense I had!

It turned out to be very simple - a seal on the boot had failed. When it rained, water was getting inside the car & onto the security ECU.

The garage that finally got to the root of this longstanding problem say that the ECU was so wet that they could pour water out of it. Obviously electronics like that don't like the damp...which is why two ECU's had failed in quick succession.

Hopefully this latest ECU will be 3rd time lucky, saved from the soggy fate of its predecessors. It just goes to show that all the fancy (and expensive!) electronics in the world are useless without a bit of rubber to protect them from the elements.

So my advice would be to check the seals if your locking & alarm system starts playing up after it rains!

Best wishes,
Lisa

Sound advice, thanks! Mike.