wipers working intermittently

[Jayw13702]

Over the last few days my wipers have been failing to work on an intermittent basis.

If the car goes over a bump then they come back on, once they are moving they only stop when you switch them off. When you go to switch them back on again and sometimes they work and many times they don't......until you hit a bump/catseye/pothole.

So pulled the scuttle panel ff today and did some digging, have a look at the video, when you flex the wiring the motor almost stalls. When Im doing this I am not moving the motor or linkage, there's no obstructions at all.

Ive checked the multiplug and can't see any corrosion, all the wires look to be in good condition. What would cause this to happen?

When the wipers fail to work if I move the wiring at that point they spring back into life, my only conclusion would be the wiring is breaking down. any other opinions? 

[Jayw13702]

Some pics of the wiring and plug






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[Bob99]

A few of us have had this problem Jason and a replacement wiper relay cured the fault. Not sure if yours is the same fault as you seem to be looking at the wiring side. Initially I would remove the wiper relays (there are two of them) located in a black box by the brake reservoir, clean the contacts and try them again. I’ve had the same problem and after changing the INT wiper relay everything was ok. eBay usually have a few for sale cheaply.

[Herbie]

I don't understand why you're asking the question because you can't have a better diagnostic result than that - something is obviously wrong with either the wiring or the connectors in the area that you're flexing.

First of all, because it's easiest, cut back the ribbed conduit so you can get access to the individual wires and flex each of them one by one. If that doesn't reveal anything then you need to take a closer look at the connectors, starting with the plug (that pin at bottom left seems to be higher than the others so maybe it's not making a good contact with its mate in the socket) and progressing (if needs be) to the socket and wiring on that side.

[Jayw13702]

I don't understand why you're asking the question because you can't have a better diagnostic result than that - something is obviously wrong with either the wiring or the connectors in the area that you're flexing.
First of all, because it's easiest, cut back the ribbed conduit so you can get access to the individual wires and flex each of them one by one. If that doesn't reveal anything then you need to take a closer look at the connectors, starting with the plug (that pin at bottom left seems to be higher than the others so maybe it's not making a good contact with its mate in the socket) and progressing (if needs be) to the socket and wiring on that side.

Whilst it may sound silly my reason for asking is affirmation, and also to save wasting time by finding out if anybody else has encountered the same problem.

You’re right it does look like the problem is on the wiring side, the relays all appear good and the contacts on the relays are nice and clean.
Next job is to try and establish which or how many wires are causing the problem and replace/repair where necessary


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[Jayw13702]

Back on the case, I am trying to do this between contract work that I’m doing at the moment.
Stripped the conduit out, with a multimeter I’ve managed to establish

white/black wire is earth,
both reds are 12v live - each one is for a different speed.
Blue is 12 the for the intermittent wiper.
Green doesn’t appear to power up.

All of the 12 V feeds are constant, no amount of wriggling the wire will produce a drop in voltage, So it would appear that the wiring side is good.

With the wiring all out of its conduit I then put it back on the motor and started trying to replicate it’s failing, the only way I could do this was on intermittent as when the motor is working it continues to work, but if you are on intermittent once the wipers have parked there is a chance that it will fail to work again.

I have almost come to the conclusion that the motor is a fault, so long as the motor continues to work it will carry on working but as soon as it stops there is a chance that it will not restart. Also on one of the few occasions that I managed to get it to fail if I were to tap the motor with something it would kick into life.

Any other thoughts or possibilities that I may have missed?




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[Herbie]

1. I'd cut that cable tie off and grip each wire to flex it close to where it enters the connector if you haven't already done that.

2. It could still be a loose or corroded connection rather than the motor itself, so I'd open the connector and/or motor casing to check that or to check voltages/continuity across the connector while flexing the wires on the plug side.

[Jayw13702]

1. I'd cut that cable tie off and grip each wire to flex it close to where it enters the connector if you haven't already done that.
2. It could still be a loose or corroded connection rather than the motor itself, so I'd open the connector and/or motor casing to check that or to check voltages/continuity across the connector while flexing the wires on the plug side.

The cable tie was pulled off just after that picture was taken, when I did all the pulling and pushing it was right down at the connector end but also the following 2 inches or so of cable.

Good shout on the continuity, that’s one that had slipped my mind


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[GS300h2014]

If the problem only shows when the wipers are used intermittently & not when used normally then I wonder if that suggests a relay problem? Has your car got a rain sensing option? I'm puzzled why there are two relays in Bob's car. If you have two identical ones; is it worth switching them to see if it changes anything?

A quote from  https://www.yourmechanic.com/article/how-to-replace-an-intermittent-wiper-relay-by-ronny-brown

'If the windshield wipers function on high and low but do not work on the intermittent setting, then your intermittent wiper relay may be faulty.'

 

[Jayw13702]

Possibly got a result!!

Stripped the motor/linkage back off the car tonight to do some continuity test. Stripped the black plastic cover off the motor to get at the electrical side of the motor.

Once I had the cover off I could see that there were two connectors that were quite dirty, these make the connection between the motor and the electrical contacts that sit within the plastic portion of the motor assembly





Cleaned them up, checked for continuity across all the terminals and put it all back together.
I no longer have the motor dragging when I move the wiring loom about, I’ve taken the car out for a 30 min drive and still have working wipers so now it’s a case of see what happens over the next few days


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[Herbie]

Excellent, great result Jason, glad it's sorted.

As an aside, I mean no offence to anyone but speaking as someone who has worked in electrical maintenance most of my life, I have to say that this was the holy grail of diagnostics - a perfect example of cause and effect.

Waggle the wires and the fault appeared; stop waggling the wires and the fault went away; ergo, the fault had to be somewhere in that area of waggled wires.

[Jayw13702]

Thanks Herbie,

It is very satisfying when you get a result like that, especially when a new motor is £270 +vat from Lexus and used ones are £100 on eBay.

The nylon wheels have given off a bit of material over the last 175,000 miles and this was just starting to gum up the internal electrical connections and cause them to break the flow of current. My understanding of electrics is basic hence my initial questions.

Thanks to everyone who helped with ideas [emoji106]


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[paulrnx]

There’s every chance that a Lexus dealer would have changed the motor. If it fixed the problem (because one half of the connection would then be brand new) then you’d have paid for a new motor and they’d think that was the cause. Worst case it would still have been faulty and they’d also replace the loom and because both halves of the connector would then be brand new this would fix it. Expensive given that it looks like the connection just needed a good clean. Great diagnosis and fix though, well done! Cheaper too!!

[Jayw13702]

There’s every chance that a Lexus dealer would have changed the motor. If it fixed the problem (because one half of the connection would then be brand new) then you’d have paid for a new motor and they’d think that was the cause. Worst case it would still have been faulty and they’d also replace the loom and because both halves of the connector would then be brand new this would fix it. Expensive given that it looks like the connection just needed a good clean. Great diagnosis and fix though, well done! Cheaper too!!

Had they (or I) replaced the motor then the issue would have been sorted, but as you say it was sorted for no cost at all [emoji106]


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[Jayw13702]

Just when I thought all was well.......the wipers packed up again today [emoji35]

Stripping the motor down properly this time I think I found the culprit




The shaft isn’t too bad but the brushes are non existent, I can only presume that messing about with it last week freed it up and gave me a little more contact area


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[Herbie]

Excellent find Jason!

It may well be worth cleaning up that comm too. As well as brightening up the copper, have a look down the slits to see if the mica needs to be undercut but be careful not to take too much out. Looking down the shaft towards the commutator the space between the copper segments should (if you imagine it magnified) look like a letter 'U'.

If it needs to be undercut then the 'U' will look almost full to the top so that there is almost no difference between the height of the copper and the height of the insulation. In other words, it should look like a gear wheel rather than a circle, if that makes sense.

EDIT: Why didn't I just go straight to YouTube?

 

 

[Jayw13702]

Excellent find Jason!
It may well be worth cleaning up that comm too. As well as brightening up the copper, have a look down the slits to see if the mica needs to be undercut but be careful not to take too much out. Looking down the shaft towards the commutator the space between the copper segments should (if you imagine it magnified) look like a letter 'U'.
If it needs to be undercut then the 'U' will look almost full to the top so that there is almost no difference between the height of the copper and the height of the insulation. In other words, it should look like a gear wheel rather than a circle, if that makes sense.
EDIT: Why didn't I just go straight to YouTube?
 
 

Thanks for the tip there.

So are you saying that it would be possible to rebrush that motor? I’m sorry if that sounds like a dumb question but I didn’t know if it would be possible

I got one of the brushes out of its holder and it looked like this.



I’m guessing I would have to get brushes and shape them down to fit in the holder.


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[Herbie]

2 minutes ago, Jayw13702 said:

So are you saying that it would be possible to rebrush that motor?

Absolutely, yes.

Not quite sure where you'd get brushes from but it may be worthwhile giving these guys a ring. I live about two miles from them and can honestly say they're brilliant.

Alternatively, go with your idea of getting generic brushes and shaping them to fit.

[Jayw13702]

I’ve managed to find some that are about the right size that will require a small amount of reshaping and the bonus was I could get them from amazon on prime delivery so they should be here tomorrow.

Thanks for the tips, hopefully by tomorrow I can have the motor properly working again


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[Mr Vlad]

Hi Jason. I've just come across your thread. Very involved what you've done.  I have to ask but do you have rain sensing wipers? I had the exact same problem. My wipers wouldn't come on on intermittent but only on constant. My problem was the rubbery plasticy sheet between the windscreen and the sensor behind the rear view mirror. My car didn't have that sheet. Once one was bought and fitted my problem was cured. I did a thread on it in the gen 2 is.

[Jayw13702]

Hi Jason. I've just come across your thread. Very involved what you've done.  I have to ask but do you have rain sensing wipers? I had the exact same problem. My wipers wouldn't come on on intermittent but only on constant. My problem was the rubbery plasticy sheet between the windscreen and the sensor behind the rear view mirror. My car didn't have that sheet. Once one was bought and fitted my problem was cured. I did a thread on it in the gen 2 is.

Thank you, it’s been enjoyable doing something I’ve never done before.

My car is SE spec so doesn’t have rain sensing wipers


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[Mr Vlad]

I tip my cap to you Jason. Your thread will no doubt be a great help to others. Well done 👍