FRONT WIPER DECEASED 250d

[colind]

Hi all,
can anyone help please !!

The front wiper on our 250d has expired, after a burning smell inside the car. I wrongly assumed it was the motor and obtained a good second hand one connected this up and guess what ?, it wont work. The combination relay can be heard clicking away when the wipers are switched on and the washers still work as does the headlight flasher which makes me think it is not the stalk switch or the relay.

Could it be possible that although the relay can be heard clicking that it is not actually functioning correctly and switching any power to the wiper motor, i have cleaned all the contacts on the relay and checked the fuses but to no avail. My next step was going to be to replace the relay but i dont want to buy a new relay if there is nothing wrong with the original.

any help greatly appreciated,

colin

 

[Dec]

What year is the car?
How did you connect up the second hand motor?
Is the relay clicking constantly or just intermittently?

You smelled burning, then there must be some evidence of damage, that is, if it was not the motor that was the cause. Have you removed trim to investigate? Is this the motor (small pic) you have? Notice the type of plug bottom right of picture

Dec
Edit; Was the wiper motor running when the burning smell was apparent, if so, in what way was the blade acting, did it stop or stutter?

 

[colind]

No Wiper

Hi Dec,

thanks for your reply, the car is 1996, my wife was driving at the time the wiper failed, she said she smelled burning then the wiper stopped in the middle of the screen and slowly went down in to the park position.

I have removed the old motor and the wiper mechanism from the car, and plugged the new motor in with the 5 pin square plug to the socket on the car to test it before re-assembling the mechanism etc, but it doesnt react at all even when the relay clicks.

The relay clicks at regular intervals when the stalk switch is operated, i have not found any evidence of damage anywhere, to explain burning smell, but i have not taken the dash/cowling off around the steering wheel yet so maybe a problem in there ?

For some reason my computer wont let me look at the little picture you have put on of the motor, not having much luck with electrical gadgets at the moment.


any advice greatfully received,


colin

 

[Dec]

Hi Colin

Re; No pictures,
In Internet Explorer
Click on Tools menu
Click on options at the bottom
Click on advanced tab
Scroll down to where it says “Show pictures” is that box checked? If not check it and click Apply then ok.
If you are working in an office this may have been disabled to stop people looking at naughty pictures when the are supposed to be working.

I have to go out, back in an hour, try the above.

Dec

 

[Dec]

Try cleaning the switch within the tip of the stalk, haven’t done this but I believe you can lever off the tip of the stalk and clean whatever contacts there are, with switch cleaner, there is a spring inside which will pop out when you remove the tip of stalk.

Other thing to do is check the second hand motor again, only this time independently of the cars electric’s
Take the back off the 5 pin plug of the motor, you can lever it off with a coin, (it push/clips back on again)
With a battery charger put Live + to the Green wire and Negative - to the White, don’t touch the other wires.

If the motor is good it will run, the Green and White go to the brushes and can be seen as two separate wires about 2 inches from the cluster of Black/Brown/Yellow wires You could do the same test on the original motor.

You could also remove the motor gearbox cover, held in place by 7 torx bolts and lever, uniformly upwards. You will see 3 switches and the rails that the run on, check their condition and clean and grease, sparingly, just enough to lubricate the switches as the run on there rails.
Check the nylon gear teeth for signs of being chewed up by the worm drive, you will not be able to see all of the teeth, just those facing the worm, however the evidence will be some nylon shavings around the worm drive. If there is any damage to the teeth of the nylon gear then the motor is nackered.

Because of the smell I think you may be right about the problem being at the stalk. I don’t know much about that area but I believe the steering wheel and air bag have to come off to replace stalk, hopefully others members can advise. Try my previous suggestion first as the will be easier to do.

Can you see pictures in post #17 HERE.
Read pages 1 and 2 HERE.

Dec

 

[colind]

No Wiper

Thanks Dec for all the advice,

I will try that with the battery charger on both motors and see if they run, you never know i may have a pair of duff motors.

I will also have a go at taking the end off the stalk and see whats inside, and give it a clean. I beleive replacing the stalk is a pig of a job as the steering wheel and air bag do have to come off, will leave that till last resort i think.

Still cant get pics something wrong with my internet explorer i think wont let me click on links either, just says not responding and freezes up.


Thanks again for all the advice i will have a go at it Saturday morning and report back.

cheers

colin

 

[Dec]

Right Colin, one last bit of advice for you and the most important thing you should do first is lubricated the mechanism under the ”turtle shell” cover as this is one of the causes of the failure of the mechanism and motor.

If you cant click on the link above , look in the DIY section, its called “How to lubricate the wiper mechanism” at the bottom.


Dec

 

[Aussie Nick]

Dec . Usually, in my experience, when it is a lubrication problem the wiper starts to stutter. There is a fair amount of warning that the wiper is having difficulty operating. Was there this kind of stutter present in this case? Also there was a burning smell which does not normally accompany the wiper lubrication problem. Further, the wiper returned to the park position which would suggest that it was not the motor.The stalk mechanism one would think should have been protected by the wiper fuse blowing.

 

[Dec]

Well she did say it stopped and returned to park position, it might have stuttered on its way back all right, the smell could also be from the motor, due to its location, if it was chewing up the nylon gears, only time will tell the tale.

Dec

 

[colind]

Wipers Update

Progress today :-

1. Tested both wiper motors with a battery charger and they both run smoothly - ruled out brocken motors.

2. Measured the voltage at the point were the motor plugs in to the car were the corresponding green and white wires pins plug in and found only very small voltage mv infact.

3. Moved inside the car and with a bit of cursing managed to get the end of the stalk switch out popped the spring in to my lap luckily. Moved the outer cover down to reveal white plastic contacts etc for the 3 speeds of the wipers all looked in order on first glance.
As i was figuring out how to clean this delicate looking mechanisn i put my head around the side of the swith to have a look at the back side of the contacts, it was then that i saw that it was badly melted and blackend, the source of the burning smell right under my wifes nose, when it must have occurred. To tell you the truth i was beggining to think she had imagined it, then came a few "I told you i could smell burning didnt i but you didnt beleive me" she wined, "of course i beleived you dear".

4. I now know that that i will have to replace the stalk switch i will ring Dronsfields Monday for a price OUCH !

5. I am still a bit puzzled though as to why the wiper fuse had not blown and why the damaged switch is still energising the relay allowing it to click at regular intervals as if all was well, although only on the slow wiper setting but no power to the motor at all.

6. I have lubricated the wiper arm mechanism and re-fitted the motor and outer trims.

7. Next step remove steering wheel and airbag etc while i am waiting for delivery of new stalk switch.


I will hopefully get there in the end,


Cheers colin

 

[Dec]

Just something to consider, instead of removing steering wheel and all that goes with that, look at the switch and see if it is possible to get the switch contact/plastic parts from a donor car in a scrap yard and fit them on to the existing stalk?

As to why the stalk should burn as it did could only be down to a build up of “copper dust” if there is such a thing, or a part of the switch becoming loose, causing a short.

However, and I don’t want to alarm you, it is possible that there is still a fault inside the motor, perhaps one of the 3 switches inside the motor (see previous picture links if you can) is shorting and it is this fault that burned the contacts inside the stalk.
If that were the case any new stalk might burn in the same way. While you tested the motor in the way I described, this did bypass the 3 switches completely. I think this is unlikely but better said than unsaid. It might be prudent to remove the 7 torx bolts on the motor gearbox just to check the 3 switches inside, no need to remove motor but be sure to unplug it first.

When the ignition is on, there is always live feed going to the wiper motor, this is because when you switch off the wiper in mid sweep the motor still needs power to bring the blade back to its park position.
Regarding the relay, it is my understanding that when the wipers is turned on to intermittent, the relay is used but when the switch is advanced to slow or fast setting the relay is not involved as the motor is run on continuous power.

Regarding the fuse, the only explanation I can think of is that the fuse wire is much stronger than the switch contacts and so the switch “fried” first, doing the job the fuse was supposed to do.


I would love to see a picture of the switch contacts as this is quite a common problem relating to the wiper and would be very useful to others.

Dec

 

[colind]

Wipers Fixed At Last

Hi all,

sorry for the delay in updating thread but been busy at work not had chance to go on computer. I have at last got wiper motion again after much debate and very sound advice on this forum.

The problem as i mentioned before turned out to be a fried stalk switch that has melted contacts that worked the wiper. These contacts are not replaceable so i had to replace the whole stalk switch. I read up on the proceedure in Mr Haynes book and it looked a bit daunting, removal of lower dash, steering wheel and air bag oooo!!!

Managed to get a s/hand stalkswitch for £58.00 from specialists.

Turned out not to be as bad as first thought took me about 2 hours in total for the whole job, the trickiest part was the two tork bolts in the back of the steering wheel that release the air-bag little buggers to get out as they are set quite deep in the plastic of the steering wheel and the access holes are quiet narrow, i found that you need narrow long tork bits mine where wide bits so made it difficult to position them and get them in and out.

I have swapped the motor to the second hand one i bought by mistake just incase it was the motor that caused the switch damage and hopefully thats the end of this little episode.

I have taken some pictures of the fried switch but i dont know how to post them on here so Dec if you would like me to email them to you let me know and thanks for all the advice you gave me saved me a good few hundred £££ by not taking it in to the local stealers.


Cheers

colin

 

[Dec]

Hi Colin

Thanks for the update and gald you got it sorted, very satisfying when you do it yourself. Check your Private Messages link, top of this page.

Dec