Rear wiper motor and purgatory.

So, how far down this rabbit hole am I? I fixed the lack of wash water, then fixed the outside leak, then the inside leak, then replaced the motor twice with second hand ones, then rebuilt one working motor out of two failed ones. Then bought a replacement cog that didnt work, and then bought a brand new replacement motor for £300 for the newer L322 that would not work with my car, but I hacked it to pieces to try and build one working motor. To say I am hacked off with this situation is a massive understatement.

My wiper motor seized, and failed to move the rear wiper. Spares are available from ebay, cheaply. I tried one but could not get the replacement gear to mesh properly with the drive gears attached to the motor (inside the unit) - there are only two gears, a worm gear attached to the motor itself and the nylon cog that turns inside. The nylon cog is the replacement part I was unable to get to mesh properly - I checked it against the original part and the original sits a bit higher on the mounting spindle and I think this may have been the cause.

Second hand parts are available on ebay, some refurbed. I have had two already, the last one worked for 5 months before the gear failed again. The second hand parts at present, range from £200-£400 with warranty from the ebayer.

I almost bought a new car after trying to fix this so many times. Then I looked at the replacement motor for the facelift car, 2010?? Thinking, "Is the tailgate really THAT different? Maybe the motor will fit?"

Discontinued part is DKD000030. MY<2007>
Facelift part is LR010920 >2008 (approx)

I had a look at pictures of the motor for the later facelift car. I thought "mmmmm those connectors look the same, but the fittings are different". As it turned out, the photo I saw online was not the LR010920.

I ordered a part with the intention of comparing and seeing if i could make it fit and secure it somehow. The part arrived. I opened up the box and to my amazement, the mechanical housing was identical to the unit and the fittings were the same and the only difference was the small electrical control module, both the new and old units have only 1 wire from the control module to the motor. However, the new motor only has one connector to connect to the car, whereas the old motor has two connectors to connect to the car.

"How hard can it be"? I thought to myself as I considered removing the new control module from the new motor and swapping it for the old one. The circuit inside the control module takes the power feed from the car, does the clever stuff and activates the power to the one wire to the motor as per instructions from the wiper stalk on the steering wheel. With the mechanicals being identical I expected this to be very simple.

STEP1 At home, I removed the control circuit from the old motor, 1 wire with solder. Hold solder iron to solder. Wire comes off. Circuit is housed in black plastic. This clips off.

Step 2 - repeat on new unit. A little more tricky as you need to gentle ease the unit off, paying attention to your old unit you can see how it will be attached. This looked easy.

GOTCHA No 1 : There were two metallic contact strips from the control circuit, hidden under the plastic. Ease these out at the same time as you ease the plastic off the metal housing (not hard at all). This was the weakness in my plan and where it all started to unravel.

NB - the "parking" of the wiper in motion seems to be controlled by a sensor on the circuit board that lines up with a little magnet on the white plastic cog.

I kind of realised that these two contact strips are being used to detect the magnet on the cog. Damn. Foiled.

Step 3 I had already lost the chance of a refund on the new part, so I took it all apart and removed the white cog. The magnet on the cog was very different to the old one, but very easy to remove by folding back a couple of brass tabs that hold the new magnet in place. I did that, and then had a cog without magnet.

Step 4 I took the ebay replacement cog, and popped the little latch that holds the magnet in place, and a little cube shaped magnet popped out.
I then took a soldering iron and melted a recess into the exact same place on the cog from the new wiper motor. I secured the magnet in the hole and then melted a little bit of the plastic on the old cog to and used it like a glue to hold the magnet onto the new cog.

Step 5 Reassemble

Step 6 take the old control module from the failed motor and solder the single connection back onto the same contact on the new motor. Fit the old plastic housing for the control module back onto the metal housing of the new unit.

...and test.

[url]The Problem[/url]

Getting it to park correctly seems to be a bit tricky and I have tried so many times to align these that I have got very frustrated with this and need some help.
I am unable to set the unit up so that the rear wiper parks correctly. Each time it switches on, it swipes 4 "and a bit" times and parks in a different place. One in every four activation of the wiper sees it return to it's correct parking spot.

First up. As far as I can tell, the gears, linkage and spindle want to be set up in the housing in a way that as soon as the motor starts to turn, the gears and linkage rotate the spindle in the direction the wiper should turn,
- i.e. left to right, counter clockwise looking at it from the outside (or clockwise as I am looking at the unit).

It seems to me that lining it up in any other position would have the gears and linkage turn the wiper spindle in a different direction would then move the wiper upwards from the park position and crash into the rear spoiler. I may be wrong.

However, when I line it up like that, it swipes the correct distance across the rear window, but seems to do the four swipes and then a little bit extra and thus ends up in a different place.

You can see in this video made by someone else, how the parts line up. I have lined my parts up as close to this as possible.

https://www.youtube.com/watch?v=mwhICgcxv7Y

I wondered if i put the magnet in the wrong way around. But second guessed that with the idea that the sensor would not be worried about a north or south pole on the magnet, and probably just reacts to the magnetic field being detected. Any ideas? Am I wrong about this ?

All I want is the wiper to park correctly in the same place every time.

Some other oddities since the Frankenmotor was created:
1) It will no longer do continuous wiping.
2) It swipes four and a bit times, parks in one of 4 places and switches off, does not swipe again until the stalk on the steering wheel is switched off and on again.
3) No water from the unit.
4) Activates as soon as ignition is switched on, even if stalk position is set to off.
5) If I try to switch it to continuous more than once, it just switches off and will not come back on until ignition is turned off and on again.


I do not know if this is due to the sensor being in the wrong place, or the gears and linkage being lined up incorrectly. Any ideas anyone ?


So, the sorry tale so far: 3 Replacement motors, 1 replacement gear and a lot of hours spent. I am clearly out of my depth. Does anyone know anything that might help?

Thanks
Mark

Update. Having dismantled this new unit in the entirety I can say for sure that the only difference between the discontinued part and the new part is the electronics and the associated connectors for connecting this to the car.

The electronics on the unit are only connected to the mechanical parts of the wire via a single core wire.

This should be easy..Right?

Not sure if it was gear alignment or the wrong sensors, or magnetic interference or the little bump stop missing from inside my frankenmotor, but it works now.

I will add some instructions to one of my other posts about this wiper motor and how I fixed it.