***Fixed*** Wipers don't work, have checked all the usual stuff.

[tunamelt]

**The issue is that the wiring to the wiper motor does not get power**

Its a perfect ski season in the Alps of Austria and I don’t have any wipers for my windshield!
Roads are wet at all times so the other drivers send the road muck all over the windshield and I can’t see.

Problem Introduction:
After sitting for 3 weeks for Christmas, these wipers started playing up. they would freeze midway through the range. then they would only work on High setting, and would freeze when switched to Low and not start again. They would work only on High and only with cold engine, but freeze when engine got hot. Now they don’t work at all under any conditions, setting or temperature.
During the troubleshooting described below, Ive discovered that there is NO VOLTAGE getting to the wiper motor on the low and high speed pins. The wire harness shows 2 Ohms resistance between harness ground wire and battery ground, so thats OK.
**The issue is that the wiring to the wiper motor does not get power**

What I’ve tried:
-No water in scuttle panel, drain not blocked.
-Checked wiper motor by feeding it 12v power and ground direct from battery. Wiper motor works great on Low and High speeds (pins 4&5), linkage is clean and free, wipers move at full power.
-Let the wipers run off direct power for some time to see if the motor overheats and stops: keeps going, no problems.
-Voltage tested the wiring harness to the wiper motor while wiper switch is on Low and High. 12v to pin 2 (park). 0v to pins 4&5 (Low and High speed) at all settings.

**The issue is that the wiring to the wiper motor does not get power**

-Tackled the massive and irritating job of accessing the engine bay fusebox on these Megane 2’s (take out battery & tray, ECU & lots of delicate wire connections). All fuses in good order and show low resistance on Multimeter. Don’t have a diagram for which is for the wipers, but all worked.
-Completely disassembled the Fusebox/UPC/OPC/“Body control Unit”/“Comfort Control Unit” combined assembly down to the printed circuit board and tested the Fujitsu relays. Again, don’t know which is for wipers but all made a click, and the end pins showed low resistance, which is good.
-Took apart steering column to access wiper switch at stalk. switch is built into the clock spring assembly, and I didn’t want to tear into that on this day. Disassembled switch from the back side of the clock spring assembly and had the thing fall apart in my hands. All internals look good, no burns. Fiddled the thing back together and all other functions still work, save for the original problem.
-Windscreen washer works, and rear wiper comes on as it should when front wiper switch is on and gear lever is set in Reverse.

**The issue is that the wiring to the wiper motor does not get power**

The only thing left to check would be the signal wires from switch to fusebox, and from fusebox to wiper motor, but I wouldn’t have the slightest idea how to track those wires down. Really not interested in tearing that fusebox out again. I’ve gotten all the these parts back together again, everything else on this car still works great, but still no wipers and I’m out of ideas! For now I have built a temporary system set up with homemade wiring, fuse and switch, wired directly from battery to the wiper motor. This way I can control the wipers from the drivers seat while driving, but this wont last long.

Guys, what else could it possibly be? I know the answer is in the mind of someone on this forum, and I’m way too proud to pay the dealership €1,000+ to start replacing parts. Any help is appreciated, please try to offer some details with your suggestions.
Cheers, Many thanks!

[grandadbobby]

Hi,
according to the almost useful Haynes manual, there is a relay in the passenger fuse box fed by fuse F1R (20amp). It doesn't give it a number though.
With all that you have checked, if it's not that, the interior multiplex has to be suspect. ( give it a tap ) this controls the wipers.
Well done on your temporary fix by the way.
Bob.

[tunamelt]

Hi,
according to the almost useful Haynes manual, there is a relay in the passenger fuse box fed by fuse F1R (20amp). It doesn't give it a number though.
With all that you have checked, if it's not that, the interior multiplex has to be suspect. ( give it a tap ) this controls the wipers.
Well done on your temporary fix by the way.
Bob.

Thanks Bob!
I have the extra complication that this vehicle is left-side drive. My interior fusebox is beside the driver. It has only one relay at the top of the fuse box, which I've just tested and is good. I'm not sure how to identify fuse F1R. The only fuse on this fuse box labelled for a wiper is to the rear wiper, and that fuse is good. I have a large 20 amp fuse labelled "ALIM UCH", which is good.

I'm very interested in your term "Interior Multiplex", because I have no idea what that refers to. Google search comes up with only an OBDII scan video in spanish or latin. Is the Interior Multiplex a piece of hardware, or is this a software I need to scan?

I want to follow up on your suggestions:
-which is fuse F1R?
-Where do I find the Interior Multiplex?

Many thanks,
Konrad

[grandadbobby]

Hi Konrad,
the interior multiplex module is the body UCH, l think you already found it, but in a right hand drive it's behind the glove box.
According to my diagram, working backwards from the windscreen motor :-
pin 1 earth
pin2 goes to engine multiplex module ( l assume a relay but very vague)
pin4 and pin5 go to fuse F9 (25amp) in engine multiplex module
By engine multiplex module, l think they mean the engine fuse box.
Maybe trawling the net might reveal which relay.
Also, when you looked at the engine fuse box, did you check underneath it for burnt out wires, quite common.

When my intermittent wipers went wrong is when I found that you can't buy a relay, they tried to sell me the uch.

Good luck, these electrics are way over complicated.
Bob.

[fredcamp2]

Front wipers. The upc (engine bay fusebox) receives the wiping requests from the uch via the multiplex network the computer then controls the following requests. Low or high speed windscreen wipers . Windscreen wiper park position. windscreen high & low speed are both fed via connector pph2 brown 12 terminal plug terminals 1 & 2 on this plug are high & low speed fed. Fuse marked marked f9 25a wiper motor. I would imagine the fault lies within the upc

[tunamelt]

Thanks Bob and Fred!
Very useful information here. I was getting confused by the new terms, but it sounds like the term "Interior Multiplex" is the same as UCH, which is the Interior fusebox. Also it sounds like the term "engine Multiplex" is the same as UPC, which is the engine area fusebox. Please let me know if I'm wrong about that. Moving forward I will need to pull out the UPC again to check the wires for burns and continuity.

***I've done some tests this weekend and have new information:***

Testing the unplugged wiper motor with a multimeter, I've found that it has continuity between pin 1(ground) and pin 5(high speed power). This means an internal short in the wiper motor, yes? (note: it still runs at all speeds from direct power, and doesn't trip my temporary 25amp fuse, so it must be a mild short).
I've ALSO found in the wire harness which plugs into the wiper motor that there is continuity from pin 1(ground) to pin 4(low speed power). This means there is a short in the wiring or the UPC itself, yes? (note: there is no voltage in the ground wire).

**This would make it a 2 piece problem: motor + UPC or wiring.**

I'm ready to buy a second-hand motor and UPC, but will wait for some feedback.
I've had the UPC out and have taken it apart. fuse f9 is good. There are no burns on the circuitry inside it and I've tested the white relays. Does anyone know which relay on the UPC operates the wipers? I can surgery out a relay and solder in a new one for a few bucks if I know which one.
I will test the wiring as Fred suggested: "windscreen high & low speed are both fed via connector pph2 brown 12 terminal plug terminals 1 & 2 on this plug are high & low speed fed". This is good stuff. Fred, are pins 1&2 going into the UPC from the UCH, or are they coming out of the UPC going to the wiper motor?

My wife wants to start throwing parts at the car, but those of us who have been here before know better.
My intuition is that we have a cooked relay or wiring, both of which can be fixed for 5 bucks and a bit of solder. Aside from that, a short in the wiper motor seems to have caused the cooked bits in the first place. We're getting there, just need a little more information on that relay, which wires to check (into and out of UPC) and a confirmation that the wiper motor should NOT show continuity between + and -.
Cheers gentlemen, have a good week!
Konrad

[grandadbobby]

Hi Konrad,
reading through this from the beginning again, I am not so sure you found the interior uch. It is completely separate from the interior fuses and is totally electronic ( you couldn't test relays in it ).
Your car being left hand drive, I don't know where it is, you may have to phone a Renault place over there.
They can be tested and repaired by specialists, but I don't think you can just swap them. They are linked to immobilizer and key card.
As for the wiper motor, if it was shorted, I think it would have blown the fuse, even on your temporary setup.
I am not an expert but when I have tested wires in the past, I have had similar readings where I expected none. If l were you, I'd just go on whether it works or not.
If you want to see what the interior uch looks like, look up ebay uk, you will see they are usually sold together with key, immobilizer and engine ecu.
If you find the interior ecu, check connectors and give it a bang, I had a Clio once with similar problems and when l banged it, everything came back on.
Had to get it repaired, but I knew it was faulty.
Sorry can't be more help.
Good luck
Bob.

[tunamelt]

Bob, that’s a HUGE help, thanks! That means I have not yet found the UCH. I can remember that the wipers would make a click from the center console when I would switch them on. That click is gone now. So then the fault could be in the UCH or the wiring to it. I will hunt it down and knock on it! Unfortunately we have a full week of snow/rain at about 16 liters each day for the next 7 days as forecast. At least the work will be inside the car rather than under the bonnet!

[tunamelt]

just in case anyone is still interested in this: I've found the UCH for this Left-side drive car. It's directly behind the interior fuse box: must remove the lower dash from under the steering wheel, remove the Fuse box and an air duct, carefully unclip/unscrew the UCH and remove wiring. I've taken apart the UCH and tested all the components that I know how to- all relays work as they should as per data sheet from the manufacturer(Omron). When I have daylight and the snow lets up, I will test the wiring going from wiper switch to UCH.

** An interesting thing happened while removing the UCH**

I wanted to be able to lock the car while the UCH was out. I opened the hood, locked the car, disconnected battery, unlocked the driver door with the hidden emergency key, removed the UCH, and then locked the driver door again with the emergency key. I munged up this process once and had to do it again, but in between those two times the wipers started working again for a short time. This means that unplugging the UCH and plugging it back in was a way of "resetting" the problem until it happened again. This brings up the question of:
VOLTAGE OVERLOAD.
The voltage at battery terminals is often close to 16v after start up. If the regulator is failing, could it overheat the electrical bits in the UCH or UPC and cause it to fail intermittently? These relays which tested good could be failing in the car under a load of 16v. The Omron datasheet (http://omronfs.omron.com/en_US/ecb/prod ... n-g8nw.pdf) for these (G8NW-2S) relays shows that they will fail after 5 minutes at 16v. This matches with the symptom that the wipers originally worked while the engine was cold, but failed when the engine got hot. That 5 minutes was possibly the time for the wiper relay to overheat. Is 15.7v-16v a normal charging voltage for these cars?

[grandadbobby]

Hi Konrad,
that seems too high from posts l have read, unless the battery was pretty flat.
If the battery has 12v, l don't think it should be more than 14v and hold at 12-13 with all switched on, lights etc.
Could you try disconnecting the alternator or take the belt off and see if the wipers work ok with no charging going on.
I know it will say stop and warning lights, but it might test your theory.
Bob.
ps if you need any more snow, we've got some.

[BrotherPlasterer]

The charging voltage seems high to me, I would expect between 14-14.8v.
Is it a new battery?

[tunamelt]

It turns out I was wrong. charging voltage was tested again and it was stable at 14.5v.
I disconnected the car battery and let the UCH circuit board rest on my desk beside the fireplace for a week to hopefully dry out and dissipate any static.
Installed the thing again this morning and magically the wipers had full function, no problems.
Went skiing all day in the Alps, felt like living in a postcard photo.
**However, on the way back down the mountain the wipers were acting up again.**
Lost all wiper function on the motorway, with the wiper blades dead in the middle of my view.
Stopped to wash the car, and suddenly the wipers were working at full function again.
Wife wants to buy a wiper motor, UPC, UCH, switch, wire loom...then sell the car.
No Way.
This is obviously an intermittent problem in the electronics.
I feel like I've pulled all the available ideas out of this discussion board(much appreciated).
The UCH is obviously suspect, but the expense of a new one + programming it makes me want to be sure.
I want to track down the point in the system where the power is lost.
My idea is to install simple wire contacts after each component so I can hook up my multimeter in mere seconds.
I'll wait until it acts up again and then test each wire link until I find the point where power stops.
The big challenge will be to track down the wiring routing of the wiper signal.
Fred gave the recommendation of PP2 pins 1&2 at the UCH, but i could not get a voltage reading from those pins while the wipers were working.
Are there any other ideas of points where I can test for voltage between the Wiper stalk and the wiper motor?
Thanks!

[grandadbobby]

Had all this type of malfunction on a Clio I got for my grandson.
I took the ecu to a man to repair it, it was done in 30 minutes, but while there I saw the equipment he was using.
It was very very sophisticated stuff.
I'm no expert but I think you are dealing with chips.
It cost £35 but it was here in England.
He used to work at Renaults and he only does Renaults.
I wish you well with your quest and I hope you fix it, but find out where you can get it repaired just in case.
Good luck
Bob.

[tunamelt]

Thanks Bob!
I'll definitely look into finding a company which can repair the computers.
For this problem, would I send the ECU, the UCH or the UPC for repair?
Vehicle inspection is due in the next few weeks, and my temporary fix won't be good enough for the Austrian authorities.
So I've got to get this finalised.
Am I correct in thinking that the UCH should be the piece I send in?
Thanks!

[grandadbobby]

Hi Konrad,
I just had to take the interior uch, I didn't take the key although he asked if I had it with me, it would have helped I guess.
I found this bloke on ebay and luckily he wasn't far away, so try your ebay and social media if you're on it.
If you find someone they will tell you what to send or take.
Good luck
Bob.