Elan Sprint Intermittent Wiper Control

[Bodmin]

Driving home in the rain today made me think how useful an intermittent wiper control would be.

I'm planning on doing some electrical work behind the dashboard on my 72 Elan Sprint shortly, and thought this would be a good opportunity to wire in an intermittent control.

I was thinking about the device from Quasar Electronics, but can't figure put how to integrate it with the two speed wiper switch. I was thinking about using the low speed circuit with the intermittent control, and leaving the fast speed untouched.

Anyone done this, or a similar installation recently?

I have plagiarised a switch diagram posted by Lowflyer which shows the wiring behind the switch.





https://quasarelectronics.co.uk/Item/qu ... controller

https://quasarelectronics.co.uk/kit-fil ... t/8093.pdf

[TBG]

I put a button as shown into the park wiring to give a single wipe when required. Works well. D

[Bodmin]

[quote="TBG"]I put a button as shown into the park wiring to give a single wipe when required. Works well. D

I must say that looks a nice easy solution - does it just need a momentary switch connected in parallel with the slow speed wires, or do other dark arts come into play?

I would still like to pursue the intermittent system unless it involves serious wiring.

[stugilmour]

This thread might help or suggest some alternatives. My SmartScreen is still working well, although I just purchased a bunch of parts to refurbish the 50 year old wiper system over the winter (dash out job ). Basically works with the stock dash switch, does two or three wipe cycles by pressing the washer button, and IIRC does not require the dash out to install, although that was a while ago. Really like the feature.

viewtopic.php?f=31&t=25502

HTH

Stu

[Bodmin]

Thanks for posting that Stu. I actually found your post when searching previously.

It does look a great option - I really like the idea of being able to combine it with the wash switch, as well as the fact no additional switches are required so the dashboard looks stock.

I note that you have rigged it up on a +2 which has slightly different wipe/wash switch configuration - yours is a combined switch unless I'm mistaken. The differences shouldn't be insurmountable, and it looks like SmartScreen may have good technical support. I think I'll give them a call tomorrow to discuss.

Thanks again.

[gherlt]

When I had my Golf 2 GTI in the 90s -which had two speed wipers only- there was an "upgrade" for the wiper system, which consisted in an electronic relais. The usage was simple and as following:
You switch the wiper on (to single speed) and off inmediately, waited the desired time interval and switched on again. From then on, the wiper would work always with the selected interval, until you switched off.
This is ideal for the Elan as absolutely no controler or secondary control is needed, just another relais.

[webbslinger]

My idea for the control switch is a Triumph overdrive switch on the column. See picture. I only thought I knew how to wire it though. It isn't wired correctly (shorts), so I will be hoping to learn something here. The wire is hanging down because I was looking at it a few days ago. Reaching for the switch on the dash is a distraction.

[Andy8421]

I had a look at the self parking circuitry on the Sprint, and there is quite a lot going on. There seemed to be too many wires to the switch. Assuming I have the right model, the self parking mechanism on the Sprint is a surprisingly subtle design.

In particular, the use of motor braking to slow the motor when the parking spot was reached was a surprise. As a result, just 'jogging' the motor to perform a single wipe may be a bit tricky. I have attached a link to a Morgan website where the author has done a great job of explaining what is going on during the run, deceleration and park phases.

https://morganrebuild.co.uk/WindscreenWiperMotor.html

You might get away with simply applying power to the 'high speed' connection to get the motor to run far enough to clear the self parking cam, but this does involve powering the motor in a way it wasn't designed to run with the slow speed brush earthed.

TBG, how did you wire your pushbutton in?

[661]

I have a variable speed intermittent wipe. The loom was done by DC Electronics so I have no idea how the magic occurred.

[Bodmin]

This unit from Retronics looks quite an interesting option.

https://retronicsonline.com/product/rwtm/

[Craven]

Andy,
I posted this way back.
viewtopic.php?f=38&t=38031&p=261121&hilit=+wipers#p261

[Andy8421]

Andy,
I posted this way back.
viewtopic.php?f=38&t=38031&p=261121&hilit=+wipers#p261

Thanks, this matches the Morgan description I linked to.

I did a bit more digging. The key with an intermittent add on is to have the electronics run the motor long enough for the 'park' cam to clear the parking switch and then have the motor run its normal parking cycle. As mentioned above and by Craven in his link, the motor when parking uses motor braking to slow down, effectively shorting the slow speed brush to earth. Good idea, except if you want to run the motor without pressing the switch.

As far as I can see, products like SmartScreen (linked to above) intercept the motor braking circuit via the slow speed connection, and disconnect it when they want to jog the motor past the parking cam - which is the way to do it. I guess the easy answer is to buy a product designed to work with the specific type of wiper motor used on the Elan.

Andy.

[Bodmin]

Thanks for the great information.

I've emailed Retrotronics about this - I await their reply.

Very interesting that the Smartsceen system looks like it may be compatible. I found a flow diagram pointing to several different versions. Looks like 040.167 would be the one to go for - I like the idea of the washer switch also activating the wipers for 3 sweeps.

[Bodmin]

Very quick response from Retronics showing a diagram with refers to the Elan wire colour coding.





Edit - sorry - that can't be right. It shows the wiper switch as having an earth connection.

I think the Sprint/S4 uses a Lucas 14W wire motor.

[Bodmin]

Just had another very quick response from Andy at Retronics. This should be the correct wiring diagram for S4/Sprint.




Looking at the block diagram for the switch shown (Lucas 35927) terminals 1 & 7 aren't used - they connect together in all switch positions.

OFF - Terminal 2 & 6 connect. On the Lotus switch Park R/LG and Slow U/LG connect

SLOW - Terminal 4 & 6 connect. On the Lotus switch Slow U/LG and Live W/LG connect

FAST - Terminal 4 & 8 connect. On the Lotus switch Fast N/LG and Live W/LG connect.

This is consistent with the block diagram for the Lotus switch.

It looks like the only surgery required is to break into the Park R/LG wire and route it through the Retronics switch using the Orange and Brown wires. Other than that its just supplying the Retronics unit with a power supply and earth.