Lotus Elan and Lotus Elan Plus 2 Forums

The wiper switch knob on my S3 Coupe looks unlike any other knob I've seen. The switch itself
has three wires and the plunger mechanism behind it, with the two hoses for the washer.

So my question is: for 36/5727 would this be the correct knob? or switch, or both?

It is the correct 'switch'.

The electrical part is a variable resistor (rheostat) to control the speed of the wiper motor, the push pull action is a mechanical pump for pumping washer fluid to the wiper blades.

It seems difficult to get motors that work properly with the rheostat (most modern wipers being just two-speed devices) so it can be difficult to make a satisfactory connection if you have replaced the wiper motor.

Many owners have disconnected the mechanical pump and use an electric washer pump operated by a switch put elsewhere.

The switch mechanism and the washer mechanism are the same as mine and are correct. The knob shape looks the same, but the "picture" within the knob is different, and not one I have seen before. The knobs I have are as shown below; the image is courtesy of Brian's encyclopedia. The one I have been struggling to find is the heater one, mine is damaged.

Yes, and the knob is not replaceable. I might be able to change the 'picture'.