I have a MY2005 XKR, and the rain sensing wipers do not operate, or at least not when I want them to.
With the switch set to 'Auto" I can be driving away with not a cloud in the sky and presto the wipers start, work for a few seconds in intermittent mode then stop. This can be anywhere between 1 day of driving to 1 week of driving, and only happen once then nothing.
I have also noticed with the switch on 'Auto" the wipers will come on as I turn the ignition on, and will do a single wipe. This happens only occasionally.
All other positions work fine.
Any Ideas?

 

We have some experience with here in the UK so I've had good reason to investigate the wiper operation.

My current and last three Jaguars have all had rain sensing wipers. I find this too sensitive as it regularly drags the wipers over an almost dry windscreen so I don't use it. However, that doesn't help with your question.

The Auto Wipe system comprises three components:

1. sensor
2. module
3. wiper stalk switch

The sensor is behind the rear view mirror and you should ensure the screen area surrounding it is completely clean to avoid false signals.



The sensor is an optical transducer which detects changes in infra-red light penetration of the windscreen caused by the light refraction of water droplets. The signal is interpreted by the BPM (Body Processor Module) to operate the wipers when sufficient drops of rain fall on the sensor area of the windscreen.

The intermittent action of the wipers, particularly when you turn on the ignition, suggests the problem could be a faulty wiper stalk switch or damage to the harness to it.

Graham

 

Mine does just about the same. When set to AUTO, it seems to work randomly, typically when not needed. No amount of rain triggers it, though, from a fine mist to a downpour. Except of course when it does work, and when it does, it is only right after the car is started, and already wet. It starts with one wipe, just like you described. Then it works for the duration of the trip. Strange.

I have not started the investigation, really. My first thought was to focus on the sensor. There is an excellent writeup here: auto-wipers-activating-bumps. This might be a good place to start. Looking at the sensor from the outside does not seem to show any obvious sign of coming undone, though. Also, my sense is that if the sensor is just slightly off, it should stop working entirely. Like I said, this is on the to-do list.

My second thought is the BPM. Maybe a hard reset at the battery could possibly maybe undo some calibration gone awry. To-do list, again.

My understanding is that the system also includes a rain sensor control module. It is supposed to interpret the (noisy) signal from the sensor, and, if necessary, activate the wipers by simulating manual stalk activation by the driver. So, 2 more suspects can be in play, I suppose, the stalk and the control module. I have no idea if this module even generates codes that could help in the diagnostic.

Let us know what you find. Sorry I cannot be more helpful.

 

Thanks everyone, Just about to head off for a weekend old farts party. I will start the wiper fix next week and keep you posted.

 

I turned mine off, it worked but was dumb and not really of benefit to me. Another toy on the car that just breaks, a toy to help warrant the hefty car price when new.

 

I agree with everyone that the rain sensing wipers are more aggravation than feature. Mine seem to work in the manner that they should, but it is still not the way I would like. I suppose it adds to the "bragging rights" but I operate mine manually.

 

Actually, it's not so much the automatic activation feature that makes the rain sensing wipers attractive, but the way they vary the wiper speed depending on the volume of rain. When heavy, the wipers go at full speed. When the rain decreases they don't necessarily stop, but they slow down to deal with the lesser amount of water, and then speed up as necessary. Of course, the auto-on function can actually be a lifesaver if your vision gets obscured by a sudden splash of water from a passing truck or some such. I think the system's most common problem is the sensor coming a bit loose and activating the wipers on bumps that jar it. A new glue disk for the sensor is the answer there ($12 on eBay).

 

Mine work fairly well, but they too can be erratic. With 170K+ high speed miles on the car, my windshield has its fair share of sand blasting chips. While the worn windshield doesn't bother me too much under most circumstances, I've always wondered if all that refracted light (from all the tiny chips) could be a cause of the occasionally errant auto-wipe function.

 

We've never had an automatic wiper operation that worked exactly as it should on any of our vehicles. They seem to have minds of their own and vary according to external conditions. I've found it far more effective to just use the intermittent settings and adjust them manually as needed....

 

I think mine work correctly, speed changes and all but they always seem to be to slow for my liking to kick in and wipe faster.

 

+1 Same here.

 

I just run them manually, as I have done for every car I have driven for the last 45 years. It doesn't seem like an arduous task to me to reach up to the stalk and make the necessary adjustments in about half a second so that they operate exactly the way that I want them to. I am also able to tell when it is dark enough to turn my headlights on without my car having to do it for me, but maybe I am just too "old school". Anyway, my wipers do run by themselves when I start the car up or run over a bump, even though they are not set on Automatic. I guess that I will just have to deal with it. I could never expect some automatic system on a car to behave exactly as I would like it to, that is why I just do it myself. I actually like being in control of my car, rather than having my car run itself for me, but we are all entitled to what we like.

 

Well, I went out and started to poke around the rear-view mirror area. Removed the plastic trim pieces, electrical connectors, and then slipped the mirror off the mount. This exposed the rain sensor, in the middle of the mirror mount on the windshield. I left the headliner console trim in place, it is not really in the way. Then, while it was raining, I turned the key on (engine off), put the wipers on Auto. Nothing.

Then, I applied light thumb pressure on the rain sensor, and, low and behold, the wipers started to work. Once the (light) rain was making the windshield specked again, the wipers activated again.

So, it seems like the sensor is somehow not properly glued to the windshield anymore, something reported here several times. On the face of it, all I need is the adhesive pad. I gather this is listed as Part# LJD3850AA. Stay tuned.

 

Fmertz,

See Stamfords comment above. 12 bucks aint bad---if it's any good. Let us know.......