Wipers what each pin does

[peteracs]

Hi All

Something which has had me wondering for a while is exactly how the connections to the wiper work to give the intermittent/slow/fast wipe. So had a quick play with the wiper motor isolated and some simple connections to the battery. These are my results which hopefully will help someone else. My reason for doing it was in case the intermittent controller goes out, I need to find a n other to replace it. Also with the HPE I was hoping to relay the supply to reduce the load on the column switches, a common burn out problem due to having the full current going through the contacts.

So on the wiper motor there are 5 connections.

Black - As expected earth
Grey - Fast wipe
Blue - Slow Wipe
Blue/White - intermittent start, moves wipers from park for short way
Blue/Black - intermittent finish, completes movement which is started by Blue/White, but stops at park position.

So, the intermittent wipe starts by a short pulse on Blue/White with Blue/Black permanently powered. Slow/Fast is controlled via a switch on the dash (at least on my pre facelift) so essentially you need 2 relays to bypass the feeds via relays if you want to totally bypass the switch on the column. There is however one thing which is confusing on the wiring diagram the Blue wire also goes to the intermittent controller, why I do not know at present, but further investigation is required……… will update when I have played further.

Peter

[WestonE]

Hi Peter

Great research. My experience is it is the fast wipe Grey wire that needs the relay because it simply does not give fast wipers until it runs via a relay. The intermittent wiring is one of the great remaining Beta Challenges for me. I would want an electronic delay device. 

[peteracs]

Hi Eric

Yes, prefer electronic myself, but have ordered a modern wiper intermittent relay to have a play with and see if suitable.

I think I half understand why the blue wire is connected to the intermittent relay/timer, the one function which is still a mystery is how the wipers return to park AFTER the column switch is returned to the off position. Somehow the intermittent relay/timer powers the wipers until it reaches park and I suspect this has something to do with the blue wire, though some more playing around is required to work it out.

Peter

[Nigel]

Gents,
I've got a relay on the grey wire and it makes a huge difference
to the 2nd speed.
I tried the same method on the blue wire but it caused an interference ,i.e. it
slowed it down, because, I think, it's function relies on going
through the intermittent relay. So curing the slow 1st speed is going to
be a wiring fix rather than a relay addition...I hope.
It may well be that the problem is within the intermittent relay itself, or the wires
that feed it. Fitting a new column switch last year made zero
difference to anything. [except to have the indicator stalk on the other side.]

An alternative solution to the intermittent relay/function is needed. A new modern
relay with a knob to adjust the delay?

[Nigel]

Quoting myself: 'An alternative solution to the intermittent relay/function is needed. A new modern
relay with a knob to adjust the delay?'

I watch with interest!

The park function is carried out within the motor itself. There's a spring contact which is
fed power after the wipers are shut down, the internal cam breaks that feed at park.

Nigel

[peteracs]

Hi Nigel

Variable intermittent, that will have to wait…….

With this playing around I noticed that the slow speed wipe was actually slower than the intermittent speed wipe which I would guess is related to the intermittent having feed from the intermittent relay and the blue wire as well. When I have figured out the park on switch off and if this new relay can reproduce the required sequence, I will have a play with relays for the blue etc.

Peter

[peteracs]

Quick answer on how it parks with switch in off position. The Blue/Black is 12V with switch in off and intermittent positions. So the motor returns to to park.

Peter

[peteracs]

Hi

A bit more progress on what does what and when.

The intermittent wiper relay has 4 wires going to it on my car (no idea if they used a different system on later cars, anyone know or has a wiring diagram?).

Red is 12V when the switch is in intermittent and slow on the stalk.
Yellow is GND when the switch is in intermittent and 12V in slow on the stalk
Blue and Blue/White appear to become 12V only when the stalk is in intermittent and only for a short pulse every few seconds.

So on to trying out a modern alternative. There appears to be some commonality of both function and pin naming for various wiper intermittent relays. I have bought and waiting for a relay via Ebay called a ZT550 which is a Chinese one. The pin outs are as follows. I have no interest in using the washer function, much prefer to do the two operations as separate ones. Also these relays do not have a variable intermittent speed function, again not something I am that worried about.

Pin outs functions are as follows (I may need to revise this…) also existing wiring colours

I - Intermittent function enable - Red
31 - GND - Yellow
53M (53E?) - Power Output complete sweep, not sure this is useful - N/C
53S (31B?) - Power Output start sweep - Blue and Blue/Black
15 - +12V - Blue/Black
T - Washer function enable - N/C

Also to improve the resistance and current through stalk issue, it would take 3 relays, one for the main power after ignition switched on which supplies the relay above and then one for the supply to the non intermittent supply and finally an optional relay to switch the slow/fast. This could be left as simply using the dash switch of course which is probably of a sufficient rating as standard and does not limit the current significantly.

So just waiting for the relay to arrive to have a play with it.

Peter

[peteracs]

Hi

Relay arrived and had a quick play, wiring above proved incorrect, details on connection were somewhat misleading from the circuits I looked at.

So my final connections were

I - intermittent wipe enable - needs 12V to activate it so use Red wire
31 - GND so use Yellow
53M/53E - Pulse output so connect to wiper start so use Blue/White
53S/31B - This is the confusing one, needs to be connected to GND to get pulses on 53M, connect to Yellow
15 - main 12V in, so provides power to both relay and to wipers to start them, Red wire
T - washer function no use so N/C

The Blue/Black wire needs to be connected as original, ie direct to the wiper motor.

I hacked together a set of test wires direct to the wiper motor for the test, so the above is my interpretation of what I found. I was not going to be stripping out the wiring under the dash, life is too short for that when the Spider’s relay works fine. I would however be pretty confident it will work without issue.

Also this relay appears to come with various part numbers and suppliers.the only downside to it is that there is no option to allow independent mounting which would have been useful. Not sure if the orientation of the pins fit and standard relay socket.

Hope this is useful to someone in the future. I do aim to try to use it on the HPE rewiring.

Peter

[WestonE]

Hi Peter

Many steering columns/pedal box frames came with a spring clip that holds a relay. It is held in place with a single self tapper screw. When I finally finish packing the garage cupboards these will re-appear in my collection. You probably have some ignored in a bitza box.

Eric

[peteracs]

Thanks Eric

I will look out for it, I have forgotten how the original fits and not that enthusiastic to get upside down again….

Here is the pin out and photo for the relay just to complete the detail.

Peter

[Nigel]

That's a great help Peter, and appears to be
a solution for dodgy existing relays and a guide
to re-wiring the whole system.

Nigel

[peteracs]

Hi Nigel

I think the original relays appear reliable even after 40 years which I guess is a testament to how simple and well built they probably are and normally in the cabin, so most folk will not need to replace them. I have yet to see any request for them or for the hazard or indicator flasher other than to allow use with LEDs where you need to replace the flasher with a modern led compatible version. With that it is a simple like for like swap in general.

My reasoning is that I am rewiring the HPE and want to get all the fuses and relays together where possible and have holders for each relay and to try to keep the relays as modern cube styles so they can be arranged compactly. I know there will be a few outlying fuses and possibly relays, but where possible keep them together so fault finding etc is kept in limited places.

Peter

[JohnFol]

Where on the vehicle is the "Windscreen wiper motor change-over switch"?

[peteracs]

Hi John

Where did you get the name from?

The only one I can think of which sort of describes it is the fast slow switch on the dash.

Peter

[JohnFol]

Haynes refers to it as item 72. One of the attachment shows you the wiring of it. The Azzurro wire on pin 3 of item 72 goes to block connector 32 that sits between intermittent unit (30) and wiper motor (22). So it sounds "involved" in the wiper motor opperation

[peteracs]

Hi John

Yes, that is the low/high speed switch on the dash, it switches the voltage between the grey and blue wires. The feed is from the column switch grey/black wire.

Peter

[JohnFol]

Haynes could be clearer.
The way it's drawn is the change over switch (72) is on the "wiper side" of the block connector (75) rather than the "stalk side", suggesting it's a separate component. It also suggests item 77 "windscreen wiper two-speed motor and washer motor control" is part of the stalk assembly and that matches your comments.

[JohnFol]

Sorry just re-read your description. Is there a button on the dash? That might be the bit I'm missing (in understanding 1st and then on car 2nd)

[peteracs]

Hi John

The wiring diagram is for a pre facelift, so if you have a facelift it may be slightly different, but looking at a facelift dash there is a button on the dash just to the left of the column which has what looks like a wiper on it? On the pre facelift you have three positions for the wiper stalk on the column, off/intermittent/on, the switch on the dash gives slow/fast in the stalk on position. I am sure someone will come along and confirm if that is different on the facelift cars.

Peter