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Discussion Starter · #1 ·
Sorry for this long posting guys.
But I feel it right that all the smallest details are made clear for all level of ability

WHY YHE HELL WONT MY FRONT WIPERS PARK

I have to say that the following is my experience I’m not a mechanic or an electrician but have owned LR for 15 years in various parts of the world. So when it come to working on them I’m not completely stupid. Therefore I can not take reasonability for damage or other damage caused due to these instructions carried out by others. This worked for me on my motor and 2 others I’ve worked on. This is my experience you follow this at your own risks.



So after a couple of years I have solved my problem. And As I see this issue posted on different forums I have the time to post my finding and result to all. I hope this will help others.
The problem I’ve had was the wipers
1) Not parking and
2) The intermittent stopping half way across the windshield.
A problem others on this forum have. And one of those things that doesn’t interfere with the daily running of the truck, but god is it friging annoying on those on and off rainy days

So after researching on this forum I started checking this out. The answer I got was the wiper motor was shot or more to the point the park relay that’s on the motor is shot. So I got a used one and it still didn’t work. I then, over a period of time picked up another 2 units. One didn’t work at all and the other worked for about a month. So I’m back to where I started. It was last weekend when I decided to spend some time to find out how this stupid park relay in the motor worked.

What I had already checked prior to this undertaking.
1) The Green wiper Relay in the Pass’ side kick panel.
I did this by swapping it with the rear wiper relay in the driver’s side kick panel. No result and as the rear worked fine I have to assume the relay was good.
2) The multifunction switch I excluded this because if these go south you’ll know it the dome light turns the cabin in to a discothèque etc etc just pull the fuse on the MFU you’ll see what I mean.
3) The switch on the steering control arm. This I find after inspection and the Haynes very poor wiring diagram, has no function to the parking and intermittent operation of the motor. It’s just switch to switch the system on & off and that’s it.

Reverse engineering time
(Before you start ripping you motor apart refer to Bench test #2 first)


I decided to focus on the motor. What makes this think tick? What is this relay on the motor everyone’s telling me about? and how does it work? Has anyone taken this thing apart? And if so why is there no posting anywhere?
Taking the motor I had that didn’t work at all. I started to take it to pieces. And this is what I found.
The motor wasn’t working because the magnet round the inside of the black housing had broken up and was jamming it up. Cleaned it out and reassembled.

#1 Now bench test time

The plug off the motor has 5 wires Blue, Red, Black, Brown, and Green. A 6th if you include the ground strap from the wiper motor wiper/linkage to the body work. This strap is very significant and I will explain later. The first 3 colors go to the motor chamber and Brown and Green go to the so called park relay mounted on the back of the gear housing.

Using an old car batteries connect the black wire to – negative and a wire on the positive battery poll, now apply the positive to the red wire on the motor plug this should set the motor running. How remove the positive from the red plug wire and do the same to the Blue. The motor runs faster IE Red speed 1 and Blue Speed two and the black is the ground for that system. If this doesn’t do the above, the motor is shot, replace the brushes of get a new one.

Next the Brown and Green wires. After reading the Green truth and the Haynes manual wiring diagrams I have established that the green wire is feed with power directly from the ignition switch. You can test this; apply a test light to the corresponding female plug connection on the truck and to the ground post adjacent.
IE Green wire Male spade to Green/Brown female spade
Now switch on the ignition the light should light up and stay on if it doesn’t there's a bad connection from the ignition switch to the wire end and this is why you wipers are not parking.
Now these Green and Brown wires running to the small black rectangular box on the side of the gear casing and are the key component to the operation of the park/intermittent system of the wiper motors.

The so called Park relay. Well there isn’t one, well not a relay in the sense of the word like the little electrically activated units behind the pass’ and Drivers kick panel.

I started by finding out what was in that little black rectangular blacks where the Gr/Br wire disappear into. I dug out the resin in the box to find the wires go to 2 Male and Female spade connector. No resistor or relays just spade connectors. This posses the question what is under the box inside the gear case. The only way to find out was to get inside, to do this I drilled out the rivets that held the cover plate down. Pry the cover of carefully and turn it over.

1st off you will see the white plastic driver gear for the wiper linkage caked in Grease. On the under side of the plate you will see 3 copper tactical like prongs. One just attached to the plate and points to the center of the gear wheel IE a ground, this is the ground that requires the ground strap I mentioned earlier from the motor body to the truck body. If you haven’t got a good ground on that strap the Park/Intermittent wont work. The other two prongs are parallel to each other and point in the direction of the gear wheel rotation.
Remove the gear and clean of the Grease. Why there is so much grease there I don’t know?????????

On the gear there is a metal disc its design is such that when the plate is closed over the gear the copper prongs made contact with the metal disc. The green wire/prong tracks on the outside edge of the disc and brown tracks round the middle section. Now remember the Green is a constant power from the ignition. If you look the brown wire prong is in continues contact with the disc during its full rotation. However the green prong only has contact with the disc for about 7/8th’s of the Discs rotation. This is because the disc’s outside edge has a 1/8th cut out section made of plastic. Where as the center part of the disc, where the ground prong is pointing is the opposite, all is plastic except where the outside edge has plastic. It’s this point that the ground makes contact with the disc completing a circuit with the brown wire.

And this is exactly how the so called relay works. When the wipers are in park the green power is not in contact with the disc therefore not completing the circuit to the Brown. The brown however is in a completed circuit to the prong pointing to the center going to Ground via the ground strap on the outside.
When you switch on the wipers then off half way on its travel the green prong/wire, the constant power feed, complete the circuit with the Brown. The Brown I believe and I’m only guessing here goes back to the MFU which over rides the switch on the steering to switch off and provides the motor with power till the Green power prong reaches it plastic none contact point cutting the power and therefore parking the wiper. This is why when you start the wipers on intermittent you hear the relay in the pass’ kick panel click on and off for a brief couple of seconds. The relay is for, I guess, kicking the motor of you didn’t need a relay to keep them going.

So I ended up cleaning the disc up with degreaser then fine emery papering and wire wooling the contact disc. I bent out the prongs to provide more tension and pressure to the disc (probably not needed??????)
Added dielectric grease where needed and greased the gearing. The reassemble was straight forward. After drilling out the rivets the easiest way to lock the plate down was to screw it, and rover were good enough to leave holes next to each rivet so you can used self tapping metal screws.



#2 Now for the Bench test
Do as for test #1 IE connect Black plug wire to Bat’ Neg- and Red Plug wire to Bat’ Pos+, this will get the motor running. Now using a battery powered test light or multimeter complete the circuit between the Green and the Brown wire. Do all this while the motor is running.
You should see the test light, light up. As the gear rotates and the green prong gets to it 1/8 section (plastic) on the disc the light will go out. It’s at that point where the light goes out the wipers park.
Now do the same with the Brown and Black. The some thing will happen but the opposite way round. The light will stay off with the exception of a brief flash as it meet the disc and completes the circuit with the Brown wire prong.
If during this test the light on either should flicker you need to go back clean out check what you did and try again. If it still flickers you're done. The prongs are worn out to far and it time for a new motor.
When refitting the wiper motor it is very important that the ground strap from the motor to the truck is a good connection this strap is the ground for the so called park relay, Check this ground with a test light or mulitmeter.
If your wipers still don’t park or have intermittent after all the above tests check out OK your problem is elsewhere and NOT a motor problem.

I also added a switch to the black test wire so I could get the gear round to the test light out position IE parked, prior to refitting the motor. I’m not sure if this matters but I did it anyway. I suggest you do it too. It just made sense that the motor should be set in park upon reassembly


[email protected]
Please feel free to email me with question; I have loads of pictures I can send you so you can identify the parts I’ve been talking about.

Also I have 2 Motors here that are if prefect working order and for a small fee + shipping I will send you one if you promise to return me your old unit. This will save you the above hassle and about $200 for a new motor. If the motor I send you doesn’t work I’ll take it back. But like I said if it doesn’t work your problem is elsewhere.
 
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