Wiper Single Sweep

There is a well documented, tried and tested means of adding a single sweep facility to the Lucas wiper system used in the Caterham.  (See: <Andrew Revill's post - L7Club> ).  This involves either tapping into the loom or interfacing the new wiring via the wiper delay unit connectors.  (If these are present - not all models have them.)  It requires a momentary two way (changeover) switch rated for the motor current, or a relay controlled by a one way (flasher type) switch.  In all cases the scheme will work with or without a wiper delay unit fitted.

However, if you do have a delay unit and you're prepared to perform some minor surgery on it then there's another way to achieve the same result that requires a one way switch and just a couple of light gauge wires soldered into the unit itself.  This can be done off the car and the existing wiring remains untouched.

The necessary changeover function is performed by one of the existing relays in the unit.   (See relay #1 on the  Wiper Delay Unit  page.)  One of its coil terminals is already connected to +12v and connecting the other to ground will mimic the function of the controller circuit and initiate a sweep.  The relay requires very little current so the rating of the switch is unimportant, as is the gauge of the wiring to it.

In the Technisol unit the switch should be connected to the two points circled in red.  (Ground is on the right):-

N.B. I don't have a Lucas unit to hand to test this,  so on your own head be it should you decide to attempt it...  but I'm 99.9% confident the following connections will achieve the same result. (Ground is on the left):-

In either case, a two pin plug and socket in the new wiring close to the delay unit (or even  just a terminal block screwed to the side) might be handy for future serviceability, but not really essential.