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Wipers wipe when I brake


Botanic
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Hello,

Now all of a sudden every time I hit the brake, both rear wiper and windshield wiper start going full speed.

Once I lift my foot off the brake they stop wiping after a few seconds.

This is very annoying and makes me not want to brake, which is not healthy...

Anyone had the same problem?

Any ideas on where to start looking?

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Odd - I would look at the wiring above the pedals and the fuse / relay board to see if anything is amiss

Are your stalks working well? - everything for the wipers goes through them, pretty cheap to replace. I replaced both sides for less than £30 for good aftermarket parts

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Short between centre brake light cable and rear wiper cable at hinge point in tailgate... common problem. The cable can fail in many odd ways in there. Unusual for the front wipers to go though. 

Or... like @LR5V mentions, could be in the stalks. There's a "how-to" fix stalks somewhere. It's the front wipers that has made me suspicious.

Edited by mk2
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I found this howto about the stalks:

 

 

It does feel like a short between the brake light and wipers. The wipers go off every time I brake and only then (unless I operate the wipers as usual with the button or lever).

How do I get my hands on the cables at hinge point? Is there a connector hidden somewhere there?

But if there is a short somewhere at the back of the car, is it possible for the front wipers to go off?

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I suppose you could test it the other way - do the brake lights go on when you put the wipers on?

32 minutes ago, Botanic said:

I found this howto about the stalks:

 

 

It does feel like a short between the brake light and wipers. The wipers go off every time I brake and only then (unless I operate the wipers as usual with the button or lever).

How do I get my hands on the cables at hinge point? Is there a connector hidden somewhere there?

But if there is a short somewhere at the back of the car, is it possible for the front wipers to go off?

That's Mk2's very good add on write up - replacing the missing pictures

The rubber boot should un-clip and peel back, if there is a break and not enough cable you may need to add a length of cable - make sure you use correct size of core, slightly bigger better than smaller - happened a lot on door looms in Mk3's

Front wipers still seem odd to be joining in, I believe front and rear wipers are ran off different relays, cant think how a signal could be going upstream to activate the fronts

 

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The trick to removing the rubber boot (the left one only) is to pull it away from the body first, by easing the rubber seal off the plastic mounting clip through which the wires and pipe go. Then to get the plastic clip out, you need to put a tiny screwdriver in between the four locating lugs that clip it into place. Each plastic sprung lug you need to ease out mm by mm till its free. To put it back, you need to put the rubber boot onto the plastic clip first. Then push the assembly back into the hole together. If you snap anything, the car will leak....

To get to the wires inside the car you need to remove the roof trim. All of it. That's a topic for another day. I need to post my "how-to" on that. Start at the sun visors in the front and work backwards. To get to the wires inside the tail gate, well, you know the rest.... 

It's quicker and easier to pull an engine out than fix the wiring going into the tail gate!

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Thanks for the not so encouraging words.

I did a quick assessment.

 

I pulled out fuse number 15 which is the fuse for the brake light.

When the fuse was out, the wipers didn't move when I hit the brake.

Both wipers worked as expected while the fuse for the brake light was missing.

 

I put back all the fuses. Then removed the fuse for the rear wiper.

Rear wiper was dead no matter what. Front wiper went off when I hit the brake.

 

The brake light functions correctly.

 

My conclusion is that there is a short between the brake light cable and both the rear and front wiper cables.

In which places are all of these three wires close to each other?

The fuse box is the only place I can guess.

What is the next step?

Edited by Botanic
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Yeah, i think (and hope for your sake) that you're right. I was thinking somewhere along the steering column but don't think so. From your good analysis, I'd say probably around the brake pedal. I wonder if the pedal box has been changed in the past and someone trapped a wire or two.

Could be around the fuse box, but it is such a lot of hassle to pull that out, i doubt it. Most likely from someone messing about with pedal box or maybe an aftermarket RKE system wired up near the fuse box. It is really unsual for the front wipers to be paired up though.

interesting problem. When you find it please post a pic...

i wonder if it's an earth problem (just an afterthought).

Edited by mk2
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I've had the car for 10 years. Pedal box has not been replaced during that time.

I've replaced the relay for the front wipers a little more than a year ago to a later model that can be programmed. The original was broken anyway.

To my knowledge that relay is only for the front wipers.

 

The timing belt and pipes for servo fluid were replaced almost a month ago by a garage.

Two days later the generator died. That one got replaced with an after market by a garage.

Now this. I can't see a connection between this and the replaced generator, but it feels a bit strange that everything is happening at once. I probably just have to accept that the car is old and  get used to this kind of things, if I'm going to keep it.

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Power steering pipe crimps do corrode away. And it's a right pain to change them.

Yeah the alternator regulator also has a corrosion joint design issue. I posted a pic of when mine went too if you have a search. And also a right pain to change (in an SDI). But almost certainly not related to wipers...

I have noticed a pattern though of corrosion related issues happeneing a few years earlier up north than down south. So maybe you're lucky (and live more to the south). By now most cars have already been through the mill. And best of all have quite a few more years to go before they will go again. :)

 

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Well I guess I live more to the North than most of you. I live in Sweden.

There are plenty of snow, ice, water and salt on the roads over here.

 

What or which part makes the rear wiper go back and forth three times when flushing the rear window?

When I hit the brake for less than a second, the rear wiper goes three times fast while the front wiper goes only once. So it behaves as if I was to flush the rear but not the front when I brake.

 

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Yes I replaced the original relay with relay 99.

Is it this relay that also controls the rear wiper and the flushing action, or is it a separate control somewhere?

The circuit board does not move about.

 

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I believe they are separate relays front and rear.

The circuit board hangs on hooks, I was wondering if it had not been clipped back in properly and has been moving about rubbing cables for a year. 

This is a stretch, but any signs of leaks into the drivers foot well - steamed up windows? recent heavy rainfall? - could be scuttle drain blocked, water finding its way into the under dash area, possibly along the bonnet pull and getting into the circuit board - big assumption being the circuit board is under the steering wheel in a LHD Lupo?

 

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Is the wiper control arm solid? What I mean is I had an idea  that there could be movement in the switch assembly when the car is braking. Forward inertia and all that.

But if it still does it when you are stationary, ignore my comment... then it is definitely electrical. I don't know the wiring layout on a LHD car.

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Primary suspect: Water.

 

Friday: Heavy rain and extreme fog.

Saturday: Wipers wipe every time I brake.

Sunday to Tuesday: Same as Saturday.

Wednesday: No driving. Car parked outside under a roof.

Thursday: All OK. Wipers and brake work normally.

 

So the problem got fixed by itself.

I haven't seen or felt any water inside the car.

The circuit board is under the steering wheel behind the fuse box.

Opening the bonnet and looking inside the space under the windshield, where the motor and arms are for the wipers, made me suspect that there is water coming in from there.

There was water dripping from the bonnet down through a hole on the cables when I opened the bonnet.

You can see that the brown cables are wet on the pictures.

Does this look normal to you? Are the cables supposed to be exposed like this, or is there something missing from my car?

https://imgur.com/a/Xv9d0c2

https://imgur.com/a/nvzAbgf

 

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I afraid the pictures don't really show much. in the UK we call that area under the windscreen a scuttle, its designed to get wet and allow water to drain out behind the front wheels. Problems can occur when leaves and mud build up in the scuttle, blocking the water from draining allowing water levels to rise up and overflow in places it shouldn't be  - but yours appears to be clean, looks like its a seal dislodged or damaged.

You need to look at any place where items pass into the foot well near the fuse box - the first place I would look is the bonnet release cable, its in the right area and fights its way through cables to the pull handle.

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Thanks for teaching me a new word 🙂

The scuttle is clean.

All the cables seen on the picture go straight down, I guess somewhere behind the fuse box. To me the cables look a little too exposed, but I have nothing to compare with.

How are the cables and the hole where the cables go in inside the scuttle supposed to be sealed?

Is the plastic hose seen on my second picture to the far right supposed to be that short? It could be 10 cm longer to cover the cables all the way I think.

How much plastic do I need to remove from underneath the steering wheel in order to see where the water might find its way?

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No problem, you guys gave us Abba, its a fair exchange!

Definitely the shelf under the steering wheel you should then be able to get a good look at the circuit board for corrosion from water ingress that may give a clue to where the leak is coming from. 

If you can, try peeling the carpet back and check the underlay for dampness, if there is a leak I would be surprised if it just got to the circuit board

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