A3 2.0DTI 2004 model 54 plate to be precise "Front Wiper Fault"

[Paul.A3-2.0TDI]

Hello all new to this site so hope you can help out.

A3 2.0DTI 2004 model 54 plate to be precise "Front Wiper Fault"

Front wiper does not work, but front washers do? I read about the bonnet switch having an affect on the front washers/wipers, - When bonnet open neither wiper or washer "front" work, when bonnet closed front washers work but front wiper does not???

I further investigated: I stripped out the driver circuit for the wiper motor located to the right of the motor, under and attached to the lid of the gear mechanisim driving the wipers. This seems to be fine visually I do not however have the instruments to test the circuitry.

I did test the input connector to this circuit board, which has three cores going to it.

One core is all brown this is earth
Another core which has two colours one is brown and cant remember the other anyway a constant 12vdc is present.
The last core is purple and has a 9.8 vdc present, the voltage maybe that because my meter is not callibrated?? dont know!

Now I know the board requires a bias voltage present to allow all conponets to operate, now the other signal should to me be a control votlage which should change condition when the wiper switch at the driver wheel changes state, but both voltages at the terminals are constant " I am guessing but would expect the purple core to be the control voltage"??

Another thing under the drivers wheel above feet pedals thier are relays which energise when the back washer is operated, back wiper operated, front washer operated, but does nothing when all conditions for front wipers are tested.

I swapped over relays "ones which were identical " I do not know what relay does what " No electrical drawing, that wouild be handy if available but might not be the problem.

I think I have shed a bit of light into this hope you can all help been working on it now for a couple of days,

Every time I need to go some where it starts to rain LOL!

Thanks

Paul Matheson

 

[NHN]

Has it had an aftermarket hid kit fitted before or now?

 

[Paul.A3-2.0TDI]

I am not sure what an HID Kit is, but I purchased car last april 2009,front wipers worked fine , until but 6 month after purchase the front wipers didnt work at times, when left sitting and switched engine back on the wipers worked fine, this sinareo happened several times until now where they dont work at all,

what is the HID Kit and how do i find out if my car has this fitted?

Thanks for the relpy

Regards

Paul Matheson

 

[NHN]

Basically mate its a xenon headlight system, if you fit aftermarket versions on the 8P it usually blows the wiper motor.

If bonnet switch is ok & no obvious breaks then get the car scanned for any errors thrown in diagnostics & then next course would be to test another wiper motor that does work, where abouts are you?

 

[Paul.A3-2.0TDI]

To be honest this audi is standard and does not have an xenon headlight system.

I am from the Inverness area.

Cheers again for reply.

Paul

 

[NHN]

Did you test the wires to see if there was a difference with bonnet catch open & shut.

 

[Paul.A3-2.0TDI]

That switch has two wires going to it and it functions as NO Normally open or NC Normally closed,

Below is just an example it might operate NO when bonnet is closed and NC when bonnet open!!!

When bonnet is shut the switch is NC and the front washer operates but front wipers dont.
When bonnet is open the switch is NO the front washer and wipers dont operate.

This tells me that the bonnet switch is not at fault.

I know I mentioned this before but when bonnet down - I operate mechanical switch on side of steering wheel - above foot pedals relays operate when switching on the back washer and wiper and front washers, but when operating all front wiper positions on mechanical switch no relay at above foot pedals energise.

This suggests that it maybe the mechanical switch or the relay for the front wipers "which relay is which I dont konw?"

But that does not answer the two voltages present at the motor control circuit terminals???

Tonight I will test the mechanical switch, but I really dont think that what is it about 5 switch functions to operate front wipers has failed all at once??

I will test also these terminals again at motor control circuit again with the bonnet open and shut but I dont think this is the problem!

Finding out the relay which energises above foot pedals when front wiper is operated might help but totally lost with this?

Thanks again for the relply.

 

[NHN]

I'll have a look in elsa to see if it clearly denotes a relay & I'd agree if washers work then its seeing the bonnet switch working for sure.

 

[NHN]

Wiper motor does have 3 wires, 2 are 2.5mm thick & this would be positive & negative feed, the 3rd is a signal wire from the central electrics module above your footwell that has shed loads of wires.

So based on this, I'm leading towards the wiper motor itself, best bet is to swap one out with another user which takes 20 minutes or so to see if yours works on there car & vice versa, overall you would be best suited to get a scan done mate aswell to see what faults are showing as I cant see any relay atm that pertains to the wiper motor/module.

Only person I know up there is Khufu & he's in Glasgow mate or around that area & then have to see if he would remove his with yours for testing.

 

[Paul.A3-2.0TDI]

OK I believe that the positive and negative feeds are the 12 volt dc bias for the control circuit for the front wiper motor just guessing though, and the control signal, which is purple core about 0.75mm2.

Now I dont know if this signal is a return to the main cpu or does the signal come from the cpu unit to activate the motor when the mechanical switch is adjusted by the user?

But when I adjust position of mechanical switch to operate all front wiper speeds the purple core control signal stays at 9.8 volts dc.

Now to me when operating mechanical switch for front wiper at low speed the purple control signal should switch on for say 2 seconds and off for 10 seconds, which runs motor for 2 seconds and off for 10??

the next position of the mechaincal switch will speed the front wipers up now the the purple control signal should switch on for say 2 seconds and off for 5 seconds which runs the motor for two seconds and off for 5???

The final position on the mechanical switch when selected should switch on front wiper for say 2 seconds and off for 2 seconds which runs the motor for two seconds and off for 2??

These are what I beleive should be the operating conditions but I might be wrong altogehter.

If my assumption is correct then regardless if motor is in fault the above should be observed on a votage tester at the purple control signal for the front wiper.

When tested the above the votage at the purple core stayed constant, now to me this is a control fault not a load fault????

I am used to dealing with 24vdc 240vac 415vac, 40-20mAmp which are a lot easier to fault find "well should be" - fault finding these cars are a nightmare LOL

Thanks again for replys

Regs

Paul

 

[Khufu]

well the early A3s are known to have a fault with the wipers. Mine have stopped twice in the 2 years ive owned mine. I believe its the linkage can stick and cause the motor to stop. I'm guessing its an overload cutout like the windows as mine started working 1st time after 5 mins & 2nd time when I left it over night. When retro fitting criuse I needed to remove it so i oiled linkages as best I could.

 

[NHN]

I would go & stick a meter on mine but tbh mate had a tall day so will have a looksy tomorrow for you mate as gotta change fuel filter aswell in same area kinda.

 

[PH1L]

the wiper motor in my 04 a3 went for no reason with similar symptoms sometimes when the wipers were running they would jusdder like a lack of power, in the end the motor packed in on the dual carriageway in the ******* rain when i was behind a lorry... sods law id speculate without a look at vagcom wiper motor

 

[Paul.A3-2.0TDI]

Thanks for all replies guys,

NHN, could you get back to me regarding the meter results on your car, I got a vauxhall tech to look at my car and he convinced its a control issue not motor fault, so that results from you would be fantastic, But fully understand if you not got the time.

I am not sure Im in right forum, just to remind my model is the 2004 54 plate a3 2.0 and this forum is for the new a3/s3 - !!!IDIOT!!!

Reason I have not put it to garage it costs money and that I do not have at leaset until I get back to work.

My GF going mental everytime she takes car out it starts raining LOL!!

Thanks again people

 

[PH1L]

it was the controller on the motor of my wipers that fried, unfortunatly its not sold seperately so new wiper it was

oh and youre in the right forum 53 plate on is the new chassis