This is a cheap conversion without going full E-code and buy original 240 headlight wiper motors.
Basically you can use any of 850, 940, 960 headlight wiper motor with minor modifications as the assemblies are essentially the same (BUT, I'm not 100%sure they didn't change the design over the time, at least the one I found in junk yard looks same). However, the rotation range of the 940/960 motor are smaller, you can go modify the gear or live with that, I will post how you can do it.(the small range rotation also looks good to me)

Quick summary:
Things you need:
1) regular had tools
2) two headlight wiper motors, better with al the harness, washer tubes and metal brackets.
3) an home made adapter(I will share the drawing of the one I made)
4) wires, 2 regular 4 pin relay, a double channel switch or 2 regular toggle switch or 2 push button switch(depends on how you want them move, I will explain the difference)
5) wiper arms, 850's looks good, but I feel they will all do the job, you will need to modify the blade as the 240 lights are much bigger.
6) zip ties, a lot. glue gun and some other small stuff that not essential.

In general, this is a 3 hours or less job once you got everything, however the result of this work really depends on how you work on it.

Basically I wanted to do this long long time ago but wasn't able to allocate good parts. They are really useful to me personally, as the place I live snows a lot and 30mins into the snow the headlights are all covered up.




And after installation


to me it looks fine and worked good, however I haven't test it in heavy snow after that cos road was too bad so I was with my suv these days.



First thing you need to do is to get the headlight wiper motor working. After you get it from the junkyard, test it with 12V. Many times they will not work but there are ways to fix them.
Here are a few issues that occurs very often on those motors:
1) snapped gear (often )
2) bad motor (not very often )
3) cracked wire (depends on which section you may not be able to fix it )
4) bad resistor (often)

Two 850 motors I got, one has bad resistor, one has a bad resistor and snapped gear.

To deal with the snapped gear:
1) carefully open the motor case
2) slightly tap on the shaft, that should push the metal plate out and u will see everything
3) check which gear was bad, if its the metal one on the shaft (rarely), then give up, go for another assembly. any of the plastic gear below the meatal plate are likely to break, however, you can interchange them with other motors and 940/960 motors. If you swapped the main driving gear with a 960/950 one, you will have to modify the gear as the stroke are not same. Pics will help understand.



the modification of this gear will provide you a 90 degree wiper rotation, otherwise its smaller, however you can use both 960 motor, then modification might not be necessary but the rotation range will be smaller

Once you got them modified, clean them and put it back, good to go.


To deal with bad resistor:

There is a small thermal resistor in the assembly housing, when they go bad you will see your motor runs at the beginning and slows down and stop. they are used to protect the motor when the wiper is stuck. There is a little counting gear to shut the power supply to the repay, once the motor did enough stroke, the replay will shut off by the counting gear, this ensures that you can active the motor with a push button and it will shut off by itself, it also ensures that the wiper arm will rest at the same position all time. (I don't really know how to explain how it works in a clear way but I will tell you what to do and what will happen )

The easiest solution is to remove it and snap the connection wire together, by doing this, you BETTER NOT depending on the counting gear to stop the motor because it the wiper stuck half way, the little gear will never break the circuit and the power supply to the motor will continue till motor burns out. this will change the way you hook up the wires as you wont be using the middle connection on the harness.

Other way is to replace the resistor, which I feel would be a big pain, but that way, you can use the replay system.

I personally removed it and just turn it on and off manually, no big deal, one issue is the wiper arm will stop in random positions, but I don't mind it.



they now stop like this, but I don't mind.

 

Continue:::

Once you got the motor running properly, you are now moving to the adapter making. I did some rough measurements and 3D-printed my adapter, works fine but not very strong, so I reinforced them with zip ties, you can make a metal one, might be better, just be creative on this part.


OEM motor

850 motor
You need an adapter to fix it on the metal structure.









not much I can say, my design is based on the 850 motor, you really need to be creative on this part. I used some bit screw to fix it on and filled with hot glue, that way this thing ban be easily removed. But its not strong enough to withstand the torque from the motor, so I zip tied it after I figured out the wiper arm position.

One thing to notice that the 850 shaft is longer, 960 might be a good fit, but that barely affects anything, I like the long shaft cos I'm not with the glass lamp, longer shaft, less force on the lamp.


Once you got the motor in, the wiring is simple. But there at some difference between each way.
#1 the relay method
If you managed changed the thermal resistor and want the wiper arm go back to its original position all time, you must use this method, this is the most complex method.

Get 2 4pin relay, one for each motor, wiring up the relay is simple. on the motor side, connect the middle pin from the harness to activation pin on your relay. The main power supply and everything are regular, but u better off using a push button switch. The logic flow is like this:
1) you press down the button, the relay activation circuits gets power, replay close and wiper starts to move
2) you release the switch once the motor starts turning, now there will be power coming from the middle pin of the harness that continues active the replay and keep the motor running
3) the counting gear moves as the motor turns, once it counts to that point, it will break the circuit of the middle pin on the harness and that pin will have no power
4) the motor stops as the middle pin will no longer keep the replay active, wiper arm will stop at the bottom of headlamp and will do so all time
This method usually wont work as you want unless you have everything in perfect condition. Also you need to separate the circuits completely either with a 2channel pushbutton or 2 pushbuttons. because the motor will not run at the same speed, if you cross connect the relay and the switch, it will run forever.

#2 The direct connection method.
This is the easiest way to do it, remove the thermal resistor or not, it will work. but the wiper arm will not rest in the sample location all time.

What can I say, wire up, put on a fuse, then manually on and off, good to go.

I personally used #2 method, but I still putted a set of relay in and I used two toggle switches cos that's what I have. personally I recommend the 2 pushbutton method cos you can adjust the position of each wiper individually and you don't need them running for a long time, just 2 or3 wipe, get rid of the snow.












don't bother the audio cable I'm using, they are strong, just keep them away from the heat, but better use good cables. Remember to seal all the connection parts especially the harness end. There is a reason I don't want the headlight wiper go with the main wiper, because I'm not using glass lamp, and the washer function of the main wiper will be used much more often, no need to damage your headlamp. So separate, use it only when snow.


The last part will be the washer tube fitting. If you got it form the junkyard, that's easy, just fish them through. If not, buy some T fittings and tubes, very easy. however use it is tricky. they go best with the toggle switch, I can turn on the switch let it run and start the main wiper washer so both of them get sprayed. once the washer pumper is of, just shut the switch.

 

As for the wiper adjustment, just pull the wiper arms off, use a zip tie to determine the location.


you will also need to modify the headlamp(the plastic case a little bit ), remove the dots.


when you test run it ,keep it wet with a spray bottle or something, avoid unnecessary damage.

I will post the adapter drawing later on.

 

The measurements were not 100% accurate, but I can adjust and modify the PLA material, if you go with metal, better make good measurements, these are just reference