It’s a simple three-way switch. Except when you come to Lucas wiper switches and motors. So why all the confusion?
The Lucas wiper motor circuit has used different motors over the years. The original design used a square case, single speed motor, labeled DR3. Cobra’s used a Lucas DR3A motor which has two speeds that had been developed using the previous design and modifying its internals to add the 2nd speed. The design is very simple, however it is kind of ‘reverse logic’ in the way it works, at least to us on this side of the pond. To incorporate the parking feature, it switches the negative side of the circuit, rather than the positive, which we are more familiar with.
As years progressed, the design evolved to a round case motor, now known as the 14W. This is the one everyone gravitates to – it is available and affordable. The circuit is still the same, the case is different as is the connector style. Typically, only the restoration folks or replica purists seek out the older square cases. Depends on ‘how accurate’ you want to be.
So, you’ve got a round case Lucas motor that came from a 60’s era British car. Worked for them, should be an easy fit to our car.
This is generally where the issues begin. If you or your mechanic are comfortable with electrical circuits and have found a used or NOS (New Old Stock) Lucas motor, just add the common US wiper motor switches and it should work – but it doesn’t. Testing the motor, you can link to the various connectors and get the motor to run, but when you hook it up, it refuses to stop at the ‘park’ position. So you go on the ‘inner-webs’ to find a solution. To make it work, you need a 3-pole switch – but how to hook it up. You find an old article on the Lucas wiper and add the modern three pole switch you found but the wiper won’t park. The secret is the switch isn’t the style the design requires. The original Lucas switch maintained contact between two of the terminals, modern switches don’t. The workaround – the circuit using a relay to emulate the original Lucas switch. Little more complicated but it works. Add the additional confusion of some Cobras used a toggle switch for the wiper switch, others used a rotary switch. The toggle style is readily available but if you’re building period-correct, it wasn’t used on the later models. And the original Lucas rotary switch – well, if you happen to have one, hold onto it, it is worth its weight in gold to the restorers. They are no longer produced and are in very short supply. (RARE!)
Oh, and if you’re building a replica and need the rotary switch style, we have a solution for that also.
So how does all this affect me? Building a replica, need help on your wiper system? We have all the Lucas items in inventory and ready to help out. Not building a replica but your own version of a Factory Five, we can help with that too. Give us a call or drop us a line.