Intermittent Wipers - (Part 2)
It's been over 2 years now since I installed the first incarnation of intermittent wiper control to my Herald 13/60, if you wish to refresh your memory then you can see above. Whilst this piece of kit has served me well it was starting to get a bit temperamental, so I needed to consider either replacing what I had with the same again or try an alternative.
The Maplin kit I used last time was versatile in that it provided variable delays to the sweep of the wipers, but I was too lazy to build another and there was no mistaking it was a big ugly box behind the dash. Nobody could see it, but I knew it was there so decided on a different route this time.
There are several options out there, a similar kit to the Maplin one from https://www.quasarelectronics.co.uk (cheap, build it yourself kit), or the SmartScreen modules that are now sold by the TSSC Club Shop or direct from http://www.smart-screen.co.uk (fairly pricey, but look good) or a Timer Delay Relay (Pic 1), I chose the latter as they are relatively cheap to buy.
Before I go into detail on how to wire in the Timer Delay Relay, I should mention that 13/60's have single speed wipers and switch to match. I have the correct wiper motor, but my switch is for a two speed motor as single speed ones are no longer available and mine died many years ago, therefore I had a spare position on the switch to use. If you have the single speed switch you'll need to find a way to overcome this.
I bought everything I needed from http://www.12voltplanet.co.uk/
Your shopping list needs to contain:
Wiper Timer Relay - 5 Sec Delay (P00966)
4 Pin Relay (P00692)
Relay Base x 2 (P00708)
Blade Terminals with tabs (P00093-10)
11amp Thin Wall Cable for:
Earth (Black)
Live from Ignition (White)
Switch to Wiper Motor (Black/Green)
You should also make yourself aware of how these Lucas Wiper Motors are wired up. They have an ignition fed unswitched positive to the motor, a switched earth through your dash switch and another earth for the self parking. The fact these are switched on the negative side and not positive is relevant as the Timer Relay can only switch a positive circuit, and this is why a standard 4 Pin Relay is also needed as these can switch either way.
The Timer Relay has 5 connections numbered 1-5, but you only need to use 2-5, No.1 is unused. You need to wire as follows (Pic 2):
2. To Wiper Motor Switch on the Dash
3. To Terminal 86 on your 4 Pin Relay
4. 12v Ignition Feed (10amp fused)
5. Earth
The 4 Pin Relay should be wired as follows:
30. Earth
85. Earth
86. From Terminal 3 on Timer Relay
87. To the existing Black/Green wire from the Wiper Switch to Wiper Motor
They say a picture paints a thousand words, so here it is as a diagram:
The only niggle I have with this set-up is that the pulse on the Timer Relay is a bit too short, and on my wiper motor the first sweep stalls almost immediately but then works absolutely fine thereafter. Alternatively if you switch it to the on position, then back to intermittent it works great from the off. Despite this niggle, it's a neat and tiny solution.