Variable (delay) sweep wiper mod (1HM 955 531A)

[lookforjoe]

EDIT - My apologies for the confusion - I meant sweep, not speed. I revised the text.

EDIT - final wiring diagram post#61
Modded Fiat Diagram post#68

EDIT 1HM 955 531 B (marked 198) should work the same - it has the timer arrow on the schematic. VW 196 will NOT provide the variable timer.

I had bought the VW "99" relay 1HM 955 531A some years back, to do the wiper delay speed sweep mod (not the basic resolve poor circuit mod)

- looking at the diagram that I found (can't find the thread right now) - it doesn't appear in fact to be variable speed sweep, just adds delayed speed sweep position - which the '87 already has...

has anyone added a variable control to the delay circuit?

 

[Dr.Jeff]

You are correct, the VW relay is not variable speed but delayed interval.

 

[Dr.Jeff]

Everyone keeps telling me a PWM is the way to control the HVAC blower with variable speed. So I imagine that would be the same for the wipers?

 

[bpimm]

Everyone keeps telling me a PWM is the way to control the HVAC blower with variable speed. So I imagine that would be the same for the wipers?

That won't work for the wipers, it'll just slow down the motor. You need a timer circuit that is variable to trigger the wiper motor to start then it will cycle and park until it gets the next trigger from the timer. I built one years ago before most cars came with them, I even tied in the rear wiper it cycled about once for every 10 cycles of the front. Simple 555 timer circuit. No I don't have any info on the one I made it was over 30 years ago.

 

[rachaeljf]

That diagram looks quite familiar. I also made one with relays to relieve the column switch of motor current. I'm not sure why you would want a variable sweep speed, surely you want a fast sweep, but at suitable intervals to keep the screen clear enough.

 

[ArtBasement]

I thought the VW relay remembers the delay you put in through the switch. Not sure how it works, but I imagined it would sweep then stop and then you need to trigger it again at the time you want the delay to be over.

 

[kmead]

The 124 has variable speed wiper speed using a rheostat on the dash as in the speed of the motor. It also adjusts the interval on the intermittent setting.

The VW unit is designed to have an interval based on the time between when you enact intermittent and a second action to set the time interval. There are two designs for this relay. One you set the interval by turning on intermittent and having it sweep and then turning it to off and then to on again to set the interval. The other version uses the intermittent setting and then pulling back on the wash feature slightly to set the interval. I prefer the one where you turn it on and then off and then on versus the later version which used the wash feature to set the time delay between sweeps.

 

[rachaeljf]

I guess if you wanted to infinitely vary the wiper motor speed you would use a PWM controller. I've done something similar with the heater blower on my Montecarlo. I used a cheap 10A module off eBay, which would probably do for the wiper motor if the mechanism is nice and free.

 

[Dr.Jeff]

I thought the VW relay remembers the delay you put in through the switch. Not sure how it works, but I imagined it would sweep then stop and then you need to trigger it again at the time you want the delay to be over.

You are right, one type of VW relay allows you to input the delay time. After which it automatically sweeps at that "delayed rate" when in that switch position. But it is only that - a "delay" in time between sweeps, not a reduced "speed" of each sweep. See the difference in semantics? The rate of the movement vs the rate of cycles.

 

[Dr.Jeff]

I guess if you wanted to infinitely vary the wiper motor speed you would use a PWM controller. I've done something similar with the heater blower on my Montecarlo. I used a cheap 10A module off eBay, which would probably do for the wiper motor if the mechanism is nice and free.View attachment 40885

That was kind of my thought Rachael. But @bpimm makes a good point....will that just be a variable reduction in the speed? Opposed to a paused interval between sweeps?

 

[rachaeljf]

Well yes, that's what I said in my first post! That's how I read Hussein's original post, that he wanted a variable speed rather than variable sweep interval. The VW 99 relay gives a variable sweep interval, in a slightly clumsy way I admit. It would be simpler to vary the interval by fitting a small pot on the dash maybe, with a 555 timer based delay circuit as Brian mentioned.

 

[Dr.Jeff]

Well yes, that's what I said in my first post! That's how I read Hussein's original post, that he wanted a variable speed rather than variable sweep interval. The VW 99 relay gives a variable sweep interval, in a slightly clumsy way I admit. It would be simpler to vary the interval by fitting a small pot on the dash maybe, with a 555 timer based delay circuit as Brian mentioned.

We're on the same page - that's what I was saying.

 

[kmead]

Two people divided by a nearly common language.
Two people divided by an almost common language.
Two people divided by a common language.

 

[rachaeljf]

Hah! Reading Hussein's original post and the replies *properly*, I think I now understand what he meant. It seems he didn't realise the 99 relay has the variable interval trick. I blame senility on my part.

 

[lookforjoe]

Well yes, that's what I said in my first post! That's how I read Hussein's original post, that he wanted a variable speed rather than variable sweep interval. The VW 99 relay gives a variable sweep interval, in a slightly clumsy way I admit. It would be simpler to vary the interval by fitting a small pot on the dash maybe, with a 555 timer based delay circuit as Brian mentioned.

That diagram looks quite familiar. I also made one with relays to relieve the column switch of motor current. I'm not sure why you would want a variable sweep speed, surely you want a fast sweep, but at suitable intervals to keep the screen clear enough.

My apologies - I did in fact mean variable (delay) interval sweep, not variable speed

The 124 has variable speed wiper speed using a rheostat on the dash as in the speed of the motor. It also adjusts the interval on the intermittent setting.

The VW unit is designed to have an interval based on the time between when you enact intermittent and a second action to set the time interval. There are two designs for this relay. One you set the interval by turning on intermittent and having it sweep and then turning it to off and then to on again to set the interval. The other version uses the intermittent setting and then pulling back on the wash feature slightly to set the interval. I prefer the one where you turn it on and then off and then on versus the later version which used the wash feature to set the time delay between sweeps.

What I couldn't figure out was how the VW unit would be triggered to set the interval of variable delay - the second action.

Finding a way to use the existing stalk would be preferable, to remove the need for an additional switch/control that has to be fiddled with. Using the wash to trigger the delay sequence seems to make sense, rather than having to move the stalk back to the off position & on again, but maybe in actual use this is easier, as you have stated in your preference?

I still don't quite understand how the two methods described work in practice - both sound very unwieldy/imprecise. How do you know how many trigger signals/delay intervals are available?

 

[rachaeljf]

Hi Hussein, I believe the 99 relay is infinitely variable, it just memorises whatever length of time you hold the wipers on for. The 99 relay would use the X1/9's wiper stalk, no extra kit needed. However, as I understand it, pulling the stalk to operate the washers triggers three sweeps of the wipers without you needing to actually move the stalk to the intermittent position. The interval setting is done by moving the stalk between intermittent and off for the desired time.

 

[lookforjoe]

Hi Hussein, I believe the 99 relay is infinitely variable, it just memorises whatever length of time you hold the wipers on for. The 99 relay would use the X1/9's wiper stalk, no extra kit needed. However, as I understand it, pulling the stalk to operate the washers triggers three sweeps of the wipers without you needing to actually move the stalk to the intermittent position. The interval setting is done by moving the stalk between intermittent and off for the desired time.

Yes - that is what I needed to understand - thank you,

I did a search & found a thread where it is described in detail : 'adding variable wipers to a w123"

"Once the wipers are turned off (for longer than the programming interval) and on again the standard fixed interval resumes. So you can program it if you like or leave it alone. The great thing about this system is how intuitive is. Turn the wiper switch to delay, turn it off again, wait until you want it to wipe again then turn it back to delay. Most cars have an adjustment ring that takes several cycles to get just right. With this system the delay is determined by direct visual feedback. All other stalk functions remain the same. I've been using it happily on an 85 300D for several months."

 

[dcioccarelli]

Yes - that is what I needed to understand - thank you,

I did a search & found a thread where it is described in detail : 'adding variable wipers to a w123"

"Once the wipers are turned off (for longer than the programming interval) and on again the standard fixed interval resumes. So you can program it if you like or leave it alone. The great thing about this system is how intuitive is. Turn the wiper switch to delay, turn it off again, wait until you want it to wipe again then turn it back to delay. Most cars have an adjustment ring that takes several cycles to get just right. With this system the delay is determined by direct visual feedback. All other stalk functions remain the same. I've been using it happily on an 85 300D for several months."

You might also want to look at the kit from Ladapower:

https://ladapower.com/catalog/niva-...2107-wiper-relay-with-pause-regulation-detail

It seems to use a "722-3777.02" part, which looks to be common in Russia. Probably similar to the VW unit.

Cheers,
Dom.

 

[lookforjoe]

So... The other question is how to add the wiring - the schematic I linked only shows 4 wires attached, 31 just has an arrow, so I'm unclear as to whether that is just intended as a link to the descriptor [VW "99" Relay] or if that is supposed to be a ground, or what...

 

[lookforjoe]

I found a thread on here from about 4 years ago where this was discussed - I probably have Rachel's schematic from that thread as the basis for this -

So, I'm still not getting the wiring swap - the schematic shows the yellow not used, and 31 not connected. Mine has no orange, so presumably I need to repurpose the yellow for the orange power feed? Also add the gn/blk to feed the washer pump?

mine is wired thus:
r = (+)
gy = (int)
y = (-) ?
bl-wh = F (whatever that is)

column switch (from 82 parts car)