Variable Intermittant Wipers

[mat_fenwick]

Dead easy - just undo the nut on the linkage (in the park position it is all in a line) and then move the wiper to the other side. At this point the linkage should still be in a line, but the opposite way round. It will all make complete sense once you see it, honest!
I tried it briefly but found the wiper constantly sitting in my field of vision more annoying than the occasional trickle of water coming up the screen, which never really was a big problem for me in the first place. I suppose I could put it in the centre if I was so inclined...

[Dollywobbler]

I've pondered that change too. Might yet try it as the linkage is squeaking so I'm likely to pull the whole lot out for a proper lube session anyway.

The trickle effect is bloody infuriating I must admit - reduced if you adjust the wiper so it sweeps nice and low on that side.

[citsncycles]

Just fitted one of these to Timex, and can confirm that it works on Mk1's too with 1 minor difference - if you want to reduce the delay you have to switch it off and back on again, as switching to constant and back makes no difference.

[Dollywobbler]

That's as I'd expect Mike. Don't think anyone said anything about being able to reset the wipe interval from full-on setting.

I very hastily swapped the relay from Green Tiger to TXD. Forget the variable intermittent - it's worth it just to have fewer wipes when you wash. PSA stuff always seems to wipe too many times, usually starting to smear again during the winter months. Annoying!

[citsncycles]

I think Mat's original post mentioned it, but I could be wrong.

[mat_fenwick]

I'm sure mine does - if it rains tomorrow I'll double check!

[frog]

Not sure if this has been mentioned. I've fitted S1 405 stalks in my bx - the wiper stalk has a half that twists controlling the intermittent interval time. Obviously they look different but they're still nice.

[mat_fenwick]

It's been mentioned, but not in any detail. Did you also have to change the relay? Were the stalks a straight swap wiring and fixing wise?

[mat_fenwick]

Just fitted one of these to Timex, and can confirm that it works on Mk1's too with 1 minor difference - if you want to reduce the delay you have to switch it off and back on again, as switching to constant and back makes no difference.

I can confirm that on mine at least, flicking briefly to full on from intermittent reduces the delay. Interestingly, it doesn't on the van. That might mean there's slighthly different relays (although both marked as 99) but I think more likely it's down to the indicator stalk switch itself.

On the Mk2 BX it appears to be a break before make type, i.e. if you move the stalk slowly from one position to the next there will be a halfway point at which the wipers will stop. So when you move from intermittent to full on, you're actually flicking them off very briefly, and it may be the tranistion from off back to intermittent (rather than the intermittent to full on transition) which actually resets the interval. If the Mk1 switchgear goes straight from one setting to the other, i.e. a make before break type (it's easier to determine going from normal to fast speed) you won't get this. Hope that makes sense!

[frog]

405 S1 stalks are a straight swap, no relay change needed. The rubber shroud on the wiper stalk (that sits inside the steering column surround does sit a touch further out but no modification needed. I'll take a picture tomorrow.

[citsncycles]

On the Mk2 BX it appears to be a break before make type, i.e. if you move the stalk slowly from one position to the next there will be a halfway point at which the wipers will stop. So when you move from intermittent to full on, you're actually flicking them off very briefly, and it may be the tranistion from off back to intermittent (rather than the intermittent to full on transition) which actually resets the interval. If the Mk1 switchgear goes straight from one setting to the other, i.e. a make before break type (it's easier to determine going from normal to fast speed) you won't get this. Hope that makes sense!

Tried this in the rain earlier (I had plenty of opportunity today) and the Mk1 switch seems to be break before make too, but it's a much smaller gap than I remember on a Mk2. While experimenting with this, I did manage to get it to alter the delay by slowly switching to constant too, so it seems that it needs to be off for a minimum period to alter the delay time.

[white exec]

Some mention of the XM wiper stalk, with its slider for variable intermittent delay.
The XM arrangement is that the standard (fuseboard) relay contains a timer circuit, which is a simple R-C one. The higher the value of R, the longer C takes to charge, and turn on its transistor to close the relay for one wipe.
The stalk just contains an additional variable (notchy slider) resistor, which just adds to the interval time.
Did find, a long time ago, that the max delay wasn't quite long enough, so as an experiment simply added another small rotary switch, with six resistors attached, in series with the stalk slider - to give delays up to 2 mins. Works fine, but rarely used, except for clearing sparse drizzle or scotch mist.

I find I have a new Bosch 0 986 335 058 (purchased from a UK L-R enthusiasts' site) in the spares, so will give it a whirl on the BX.

The good thing about just having a slider (or rotary switch) for the variable interval is that you don't have to remember how to operate it! Not having to remember things gets increasingly attractive sometimes!

[Defender110]

Holy thread revival....ahhhh the good old days!

[white exec]

Well, I'm going to resurrect this again.
After a decent interval...?

I tried the Bosch programmable wiper relay (0 986 335 058) in the '92 BX, and although it successfully memorised the delays fed into it, it was a bit haphazard, and gave some unexpected double-wipes and a few other mishaps. Essentially it worked, but you had to think about what you were doing, which isn't the best when driving in rain.

My own preference is for an XM-type control, where you switch the stalk to Intermittent, and then choose (a slide on the XM) the delay you need, and can tweak it as needed - a simple enough arrangement.

Looking at the BX fixed-interval arrangement, this is achieved by the wash-wipe relay on the fuseboard - blue Bitron cube relay, 3rd from left, a 6-pin jobby (marked Bitron 12V 2047029 on the one here).

Interestingly, the timer chip inside the relay turns out to be a standard U642 (wash-wipe) i.c., for which there is a splendidly informative 6-page data sheet:
https://www.alldatasheet.com/datasheet- ... U642B.html

It turns out that Citroen (Bitron) used this chip and its specified circuit to the letter for the relay and the wash-wipe wiring.

The really encouraging bit on page 1 reads as follows:
. . . "Added value can be provided with an individual, continuous adjustment of the interval pause by a potentiometer, which may be built into the stalk."

Adding the potentiometer/variable resistance turns out to be childsplay, and simply involves cutting one wire at the 7-way wiper switch connector (pin #1), and inserting the variable resistance there:
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? click to enlarge

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Resistance and Delay time
By doing a few tests, I found that the maximum resistance that can be inserted is about 135k, which produces a wiper delay of 39-40 seconds. Beyond that, the relay doesn't instantly trigger or re-trigger, so 40s is the max interval possible (unless you want to start altering the internal relay components, which I wanted to avoid).

So, based on some previous experience, I settled on delay intervals of
4/5 secs (the in-built original time) - achieved with no resistance added
10s
15s
20s
30s
40s
and also decided to do this in steps, rather than as a continuous potentiometer sweep.
The resistances are a simple series arrangement (no grounding).

Steps (using a 6-position rotary switch) are easy to set, and can even be "set blind" without needing to glance at the switch. Also, a 130-135k linear potentiometer would be a bugger to find, not easy to control the shorter timings.

So, that's it.
In practice, on the BX here, the rotary 6-position switch will go in the recessed switch-cubby, next to the mirror control.

[Jaba]

Fiendishly clever Chris.