Thread: Intermittent wipers on RR L322 not working.

Rob, on the Vogue they aren't intermittent wipers in the sense that you are used to with the P38A.

They are rain-sensing. The sensor is behind the mirror.

If your windscreen has been replaced, the sensors need to be recalibrated with the new screen.

See my posts starting at page 4 on this thread: fullfatrr.com - View topic - Windscreen Replacement

Where would I be without you. Should have stuck to the P38 eh, more my vintage.

Yep, the windscreen has been replaced. And you can bet it hasnt been calibrated. I get a serious amount of wind noise too, but even putting tape over various parts I cant seem to locate it. That trim around the windscreen wipers might have been removed to replace the screen, wondering if that wasnt refitted properly.

So even though they are rain sensitive, does the intermittent speed control work like the P38 or does it actually alter the sensitivity of the screen sensor system?

There are a couple of posts on FullFatRR about wind noise after screen replacement. The top screen trim should be flush and should be replaced but the screen fitters use the old one. Noise also come from the area around the wipers. When I get home from the LR Expo tonight, I'll look for the posts.

The variable control affects sensitivity. Also, when the wipers are on low speed and you come to a stop, the wipers go to intermittent. If they are on high speed and you stop, they go to low speed.

Try spraying water onto the screen up near the mirror.

My screen hadn't been recalibrated either. I used Faultmate to do mine. I haven't yet got a red lead for my T4 to talk to the L322.

If you need to borrow a sensor, I have a spare I bought when I thought mine had failed. It was sensitive to battery voltage. A new battery fixed it.

From your old post:

There is a Rain Sensor Adaption feature to recalibrate the sensor after a windscreen change. Mine hadn't been done when the screen was changed.
(Later)
Well, after adaption, my rain sensor is working nearly properly again. It is no longer necessary to have it on the most sensitive setting in the hope it might wipe the screen. I've had to turn the sensitivity right down. I suspect it's overly sensitive because the light sensor is receiving no light and the system assumes it's night time.

At least it rained yesterday afternoon so I could test it - the sky was cloudless today. Very Happy

Now, do I go back to the windscreen suppliers and complain the light sensor is blanked off (it's probably the screen for a later non-BMW model) or do I remove the rain sensor and pare away a bit of the mask at the correct light sensor position?

Not sure what to look for here, so heading out to the shed now to try and understand it. There is that red dome under the mirror, but that seems to be part of the alarm system. Will try and look for the masked area of the windscreen and see what I can see.

Took a look. Damn difficult to photograph but here's what I found. Firstly the oval window isnt clear, its like an adhesive area that looks dodgy. Next, from inside the plastic case doesnt line up at all. Too far to drivers side. Next, there appears to be two T shaped lines in blue, one each side of the oval cut out area. One of these can be totally seen, the other only the tail can be seen. These may be some sort of guide marker to assist the location but clearly someone didnt care enough. I presume I'm going to have to get this off the screen somehow and line it up properly. No wonder things dont work properly!

The unit attached to the windscreen, is that just for the rain sensor or does it do other things? Reason I ask is that when the car is facing into the sun whilst driving, the AC goes nuts and in to full fan mode. Makes me wonder if there is a temp sensor in that same area that affects the AC?

The surface where the sensor is mounted (it clips into place) looks as dodgy as. I suspect the windscreen install mob screwed it up.

Did you try spraying water from your garden hose up there? If so, did the wipers work?

As far as I'm aware, it's just a rain sensor on the screen. There is a light sensor in it which, I believe, makes adjustments to the rain sensor sensitivity at night.

The rain sensor is located at the upper edge of the windscreen, behind the interior rear view mirror. The sensor ismounted on an optical unit which is heat bonded to the inner surface of the windscreen during manufacture. If damage
occurs to the optical unit or the windscreen, then a new windscreen will be required and fitment can only be performed
by an authorised Land Rover dealer.
The rain sensor unit attaches to the optical unit via four clips which latch onto formed tags on the optical unit. Positive
retention is achieved by two retaining clips which force the clips onto the tags. The retaining clips must be withdrawn
to facilitate sensor removal.
The sensor provides information to the BCU, via the K bus, for the optimum wiper operation for the prevailing
conditions to maintain the screen in a clear condition at all times. The rain sensor is an optical unit which operates on
an infrared waveband. The sensor uses the principle of the laws of reflection on interfacing surfaces between
materials with differing refraction indices.

As the screen becomes dirtier or wetter, the received light is evaluated by therain sensor and translated into a signal value. A micro-controller within the sensor monitors the change in signal and
initiates the appropriate wipe cycle via K bus signals to the BCU.
The software can compensate for the long term effects of scratches and stone chips in the area of the optical unit and
the short term effects of dirt or smears caused by worn wiper blades. A heater element is also contained within the
rain sensor and uses ambient temperature K bus signals from the instrument pack to keep the optical unit clear of
frost or condensation.

A light sensor is incorporated into the sensor and is used to increase the sensitivity of the sensor when light levels are
low. This feature counteracts the effects of rain on the windscreen affecting the driver's vision during night time driving.

There is a sunlight sensor on the front of the dash on the Vogue. Maybe that's controlling the AC. See item 9 in in the pic.

Sunlight Sensor
The sunlight sensor consists of two photoelectric cells that provide the ATC ECU with inputs of light intensity, one as
sensed coming from the left of the vehicle and one as sensed coming from the right. The inputs are a measure of the
solar heating effect on vehicle occupants and used by the ATC ECU to adjust blower speed, temperature and
distribution to improve comfort. The sensor is installed in the centre of the fascia upper surface.
If one of the photoelectric cells is faulty, the output from the other photoelectric cell is used for both sides of the vehicle.
If both photoelectric cells are faulty, the ATC ECU uses a default value of zero.

The red light (which looks like it came off the roof of a Seventies ambulance) under the mirror is for the alarm. If you press the lock button a second time it will turn off the interior sensing and the red light with stop flashing for a short while to confirm. Very useful to stop the alarm sounding when your fridge fan turns on and disturbs the air in the cabin.

Do you have a copy of RAVE?

AC Control.JPG

No, I don't have RAVE. Had a printed electrical manual from the factory for the P38 but nothing for the L322.

So an interesting and typically over complex system.

Red porn star light under the mirror for alarm, huge sensor box somehow attached to the windscreen which I'm going to have to try to get apart and remove from the screen, and today I noticed a second red tab in the centre of the dash near the windscreen demisting vents?

Si I had better start by trying to remove the wiper sensor and see how it's been attached to the screen. that smearing looking substance reeks of silicon on the sensor to hold it to the screen, Can't be good!

Have you had that black box apart or off the screen? Any tips to get it off and / or apart?