Wiper troubles on my rebuild

dag019 · Mar 22, 2023

On doing some more testing of the electrics I appear to have a front wiper fault. First fault is they will not park and just stop whenever the switch is turned off and secondly they do not have the intermittent function. I do not know if these two are linked and have yet to play around with a multimeter but I am assuming it is a safe bet to start with the park switch as this is a complete unknown that came with the donor motor?
I am planning on pulling a wiring diagram to check but assume there should be a permeant live to the motor somewhere to allow the park function to work. and similarly at the same time I can test for each of the three speeds (intermittent, normal, fast) at the motor as well?

Is there anything else I should be checking or some easy fault finding test i can do to diagnose rather than just guess and fit new parts?

tottot · Mar 23, 2023

Yes there is a permeant live at the wiper motor plug [ ignition on ] May well be worth checking that the wiper switch is doing its job, that each of its outputs is working.

dag019 · Mar 23, 2023

tottot said:
Yes there is a permeant live at the wiper motor plug [ ignition on ] May well be worth checking that the wiper switch is doing its job, that each of its outputs is working.

I assumed there was. That is going to be my first thing to check. Then The park switch followed by the wiper switch itself. The loom was supplied with bare connectors and I had to swap them into the plastic connector block. So there is also the possibility I have got some in the incorrect position. Some studying of the wiring diagram and some time with a multi meter at the weekend hopefully will Diagnose the issue.

nobber · Mar 23, 2023

Intermittent wipers? Thats posh.

dag019 · Mar 23, 2023

nobber said:
Intermittent wipers? Thats posh.

I say intermittent it is the slow speed, when you move the stalk to the down position.

tottot · Mar 23, 2023

Pre tdi models if you pressed wiper stalk down from the off position you get one wipe before it sprang back to off Sort of driver controlled intermittent.

dag019 · Mar 25, 2023

I have done some playing with the multimeter today at the motor end. I have permeant power so I am assuming that my lack of park is due to a faulty switch so will order a new one of those. The park swicth came with the motor fomr my donor bulkhead so is unknown. I assume thy are not all equal so if anyone has recommendations of a good brand it would be appreciated.

Also on a quick search this looks to be correct but can someone confirm this is the correct way to wire the park switch to the motor?

My findings at the motor end are:
green - ignition 12V
green/red - medium speed 12V (switch on click upward)
blue - fast speed 12V (switch 2 click upwards)
brown - nothing (I assume this should be slow speed/one click down)

Tomorrow I will check the switch end to ensure I have output power for the slow speed (one click down). I am hoping that I don't as that would mean the switch is at fault and can be replaced. The switch came from my donor dashboard so is unknown whereas the loom is brand new form autosparks so I am hoping the issue is either switch or motor not the wiring/resistors/relays in between!

dag019 · Mar 25, 2023

Looking at the above wiring diagram I am wondering if my lack of park and lack of slow speed/intermittent (one click down) are connected and is a relay issue (also an unknown form donor bulklhead) I am asusiming that if I have the correct outputs form the switch then it will be a failed relay? Am I correct in assuming that the relay is responsible for both park and the intermittent/slowest speed wipe?

dag019 · Mar 26, 2023

I cannot make sense of this wiring diagram. I am trying to work out what colours form the switch should be showing 12v in each switch positions. But I cannot work out the switch numbers in the diagram relative to the actual position of the stalk.

I have done some testing with the multimeter and I have the following at the switch:
Green - Ignition 12v
green black - 12v when the washer switch is pressed (the washers work)
green red - 12v when the stalk is one position up (the wiper work with no park)
green blue - 12v when the stalk is two positions up (the wiper work with no park)
green white - 12v when the stalk is one position down (no wipers)
green yellow - does not register 12v in any position

From this I am guessing the switch is at fault as if I understand the diagram above the green yellow should have 12v in more than 1 of the stalk positions?

Can anyone give me what wires should be live in each stalk position?

Also I assume I need more than just the 12v form the green white to get the relay to work for the intermittent (one positions down) wipers to work otherwise I would have working wipers in the slow speed as well I would just not have park?

Brown · Mar 27, 2023

If you've not done so already, it is well worth trying a new wiper relay. I find a new one of these can remedy a variety of misbehaviour. They're more than just a relay - they've got printed circuit boards inside them, so there's plenty to go wrong.

dag019 · Mar 27, 2023

Brown said:
If you've not done so already, it is well worth trying a new wiper relay. I find a new one of these can remedy a variety of misbehaviour. They're more than just a relay - they've got printed circuit boards inside them, so there's plenty to go wrong.

I have ordered a new relay, stalk and park switch. I already have a spare indicator switch on the shelf if the switch isn't to blame I will have a wiper stalk as well! I will start with the relay and see what happens. I know there is timers etc in there for the "intermittent" wipe. I still trying to work out when the green/yellow wire should have 12v as it goes to the relay, and if it should be powered at some point does not appear to be.

Brown · Mar 27, 2023

dag019 said:
I have ordered a new relay, stalk and park switch. I already have a spare indicator switch on the shelf if the switch isn't to blame I will have a wiper stalk as well! I will start with the relay and see what happens. I know there is timers etc in there for the "intermittent" wipe. I still trying to work out when the green/yellow wire should have 12v as it goes to the relay, and if it should be powered at some point does not appear to be.

Fortunately, my wipers have been reasonably well behaved for the last three years or so, so I can't remember what coloured wires do what. There's lots of switches represented in the stalk unit in that diagram but it doesn't say what stalk position does to them!

dag019 · Mar 27, 2023

Brown said:
There's lots of switches represented in the stalk unit in that diagram but it doesn't say what stalk position does to them!

That is exactly the issue I am having! The labels do not help either as there is two flick wipe switches as well as the fast, slow intermediate I was expecting.

mystery · Mar 28, 2023

dag019 · Mar 30, 2023

Well parts arrived today so I had a go at fixing the wipers. I now have park! it was at the wrong end of the cycle so I had to dismantle the motor and move the plastic ramp 180 degrees but that was easy enough. The issue was most definitely the relay. What was fitted was a flasher relay:

Although I know I should have paid more attention I am not taking all of the blame for this one as I swapped over the relays that were on the donor bulkhead matching the plug wire colours to make sure I got the correct relay in the correct place. However this has not solved all of the problems as although I now have a fully functioning medium and fast speed that parks correctly I still have nothing for slow speed when moving the switch one position down. I will have a play with a multimeter next time which I did not have with me today and check the relay end to try and work out what is going on and see if I can follow why I still do not have the slow speed. I swapped the stalk over for a new one and it made no difference and did not bother swapping the park switches as that is working correctly now the right relay is fitted.

Which of the wiring diagrams above from @mystery is the switch wiring diagram for the slow speed?

Any one got any suggestions for other things to try, at this point everything other than the motor is new!

Discodevon · Mar 30, 2023

Hi mate how the rebuild doing now? Did you ever get round to undercoating ?

dag019 · Mar 31, 2023

Discodevon said:
Hi mate how the rebuild doing now? Did you ever get round to undercoating ?

It is nearing completion. My list of things is getting smaller and thankfully the wipers are the first part I have fitted that has not worked correctly. The rebuild thread is here (LINK) if you are interested and the undercoating thread is here (LINK). I have managed to do the inside of the chassis with dinitrol, but I need a volunteer (the wife is less than willing) to help me bleed the clutch so I can drive it outside and up on ramps to wash down and then dinitrol the underside. The big things left on the list along with undercoating are fitting the radiator fan, fitting the roof lining and getting the wipers to work.

mystery · Mar 31, 2023

Which column switch is fitted the PRC3900 OR THE PRC3730

dag019 · Mar 31, 2023

Well fitting the replacement park switch has fixed the intermittent wipe fault. So I now have working wipers which is a big step Forward.

Wiper troubles on my rebuild

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