A few weeks ago my wipers began having a mind of their own. My wipers were always set to position 2 on auto so the rain sensing function could perform. Then one day they started coming on intermittently as if it sensed rain. So I switched them to position 1 or "off" and they continued to come on randomly even in the off position. I replaced the switch (used from eBay) and problem continues to occur. It seems that if I start the car and they wipe once in the first 30 secs I know that they are going to behave erraticly during the drive. If I start the car and no wipe then they stay off during the drive.
I feel like they come on more during night time driving and it seems like half of the time when I hit a bump it will cause them to wipe 1-3 times. This leads me to believe there is a wire loose or exposed. I have read that the sensor behind the mirror as well as the sticky pad can cause wiper issues but wanted some advice before I began trying to solve the issue. So if anyone has had a similar issue or has an educated guess on where to begin it would be appreciated.

 

Z20, when I have seen this in other vehicles, it has been a problem with the wiring harness in the steering column. By chance, do you move the steering column up and down a lot (say you raise it to get out of the car and then lower it back down once you get seated)? This would lead to the wearing of the wire bundle in the steering column.

 

I don't personally move the steering wheel but it seems that the car automatically moves the steering wheel upon start and stop of the ignition therefore the column does move a lot. On the positive it seems that the wiring is fairly accessible. I'll check for a loose connection or exposed wire and then do some preventive maintenance to reduce any movement in the harness. Thank you for the reply.

 

Have you noticed your full beam headlamps flickering/flashing on when they should not be, or have you had any intermittent airbag/SRS lamp flashes that seem to clear all on their own? Sometimes they appear, along with wiper malfunctions, when the clockspring in the steering wheel gets dirty or worn.

I know the lighting stalk (which is used across many of JLR models since the XF was designed) has a fairly common fault in earlier cars where the plastic 'stops' used to define the switch positions would wear down and cause a loose fit. Driving over bumps and touching the stalk with your fingers could intermittently cause the lamps to activate. I've not personally seen that fault affect a wiper stalk, but I suspect the designs are similar and your description of it faulting when driving over bumps is the same symptom. Is there any play in the stalk (both the ring and forward/backward movement)? There shouldn't be any, so worth checking.

If you are checking for loose wires be aware of the steering wheel airbag and make sure you are not sitting in front of it when wiggling connectors around. The chances of deployment should be virtually nil, but if you do have one or more worn wires there is a chance one of them might activate the detonator.

 

Xdave I've had no headlight flickering nor have I had any sort of warning lights at all come on and off. I guess it's possible that the used stalk purchased from eBay could also be broken but that would surprise me that it had the exact identical issue. There is no extra or unusual play in the stalk. All aspects of it seem very firm. And I'll heed your warning about the airbags because that would be a true double whammy on my face and wallet, lol.
In you opinion should I look anywhere else other than the steering column for a wiring issue? I plan to start there and see what we can figure out. Thanks for your help as well.

 

It's not impossible to get parts with the exact same fault from eBay. As I said I haven't seen it affecting a wiper stalk (yet!) but have replaced three lamp stalks now (both X350s and my X351) and I bought 5 used replacements to get 3 working ones.

However as you mention no play in the stalk it sounds unlikely - all the faulty lamp stalks I have seen have been loose.

I am unsure if the sensor in the mirror housing could trigger your symptom - it doesn't seem to fit with activation when driving over bumps.

I would drop the upper steering column trim off and have a good look at the wiring as Thermo suggests, and give the clock spring a blast with an air duster and if dirty a contact cleaner (with the airbag disconnected). If you remove the spring assembly for any reason note the arrow that indicates the mounting position and match it on reassembly. Remove and reseat each connector checking the pins to ensure they are seated in the housings correctly and not pushed out.

 

Earlier today my auto electrician had some free time and we had a look at the stalk, the stalk connection, the wiring harness and connection around the steering column. Everything appeared to be perfect.
After that we looked at the rear view mirror area and tested that the rain sensor was working properly by putting some water on the windshield and as soon as water was applied the wipers swiped as they should. Then we turned the wipers to the off switch and sprayed water and they again swiped in the off position. Does this mean that there is an issue in or around the sensor area? Or is the sensor doing its job and my problem has to do with the off switch not breaking the connection? I will say that the sticky pad around the sensor appears to have some air bubbles that are visible from the outside of the car.
As always any help, ideas or advice is greatly appreciated.

 

I have just poured a bottle of water over my windscreen with the stalk set to off but the ignition on and there was no response. I tried moving the selector ring around as well and there was still no response.

There is nothing in the workshop manual for diagnosing unwanted wipes.

Given how easy it is to swap the stalks after removing the cover can you get to a dealer and ask nicely if you can just test with a new part from their stock bins to rule it out? My local would accommodate that, but not all dealers are so friendly.

I've attached the wiring schematic for the wiper system. It is pretty simple with few components. The mirror/glass sensor and the stalk both communicate with the junction box behind the rear seats via a LIN bus and resistive divider respectively. Frustratingly the schematics no longer show the resistor values as they did with previous models making it harder to test for faulty stalks with a multimeter, but maybe it will help you. If you can find the resistance of the OFF position you could temporarily disconnect that wire a the stalk or junction box and use a resistor to trick it and see if the wipers still activate. If you remove the stalk and place a multimeter across pins pins 6 and 8 with the switch set to the off position, it should read the same stable resistance no matter how much you bang the switch around - if it changes at all then replace the switch.

(The stalk wiring does not go via the clockspring - thinking about it again it is obvious really as the stalks are fixed to the column not the wheel so ignore that suggestion from my earlier post. It would only be something to check if there were shared grounds involved, which does not appear to apply to this circuit.)

If still not joy it may be worth swapping relay 8 in the engine junction box with a similar one to test that the activation is not just random, or a faulty coil. At that point as you have already changed the stalk, albeit I think with a used one that may also have been faulty although unlikely, it would be worth connecting to the car for the diagnostic codes to see if the central junction box is reporting anything.

 

xdave, thank you for the response. I like your dealer way better than the one out here. I'm surprised they don't charge for parking at my local dealership, so I'm a little pessimistic that they would do anything nice/helpful, but I will try. After I can 100% determine the stalk isn't the issue (hopefully it is!) then I will take your helpful advice and proceed. Reguardless I will report back hopefully with a solution but possibly more questions. Fortunately I live in the desert and pulling the fuse to save my sanity hasn't been an issue.