Cool CatTM

Windshield Wiper Controllers

Now available for all series Alpines.

WHY WE NEED A WIPER CONTROL UNIT

A true story By Ed "Cool Cat" Esslinger

The Symptoms

This all started with that funny feeling you get, when you smell something burning, as you are driving down the road.  You roll the window down and hope it's coming from outside the car.  No such luck for me this time.  I pulled over to the side of the road and stopped the engine.  Upon investigating, I discovered the smell was coming from the area of the wiper motor.  I touched the motor and found it to be extremely hot.  I discovered that I had left the wiper switch on from the last time I had driven the car in the rain.  I turned the wiper switch off, got back in the car and started down the road, after a few blocks that smell was back, as bad as ever.  Can't be the wiper this time as I have turned off the switch.  Stopped the car again and touched the wiper motor, discovered that it was still getting very hot.  About this time I discovered that the wiper blades were not quite to the normal park position.  I tried to lift the wiper blades and found they were stuck to the windshield I have no idea what caused them to stick.  After freeing up the wiper blades, I turned on the ignition switch the wipers went to the park position and the motor did not heat up again.

The Problem

I decided to find out how this problem could occur.  The Lucas Wiper motor is controlled by grounding the wires at the wiper switch or at the park switch on the motor.  12 volts is supplied to the motor anytime the ignition switch is on.  Rootes assumed that you would always turn off the wiper switch before the ignition switch was turned off.  If this is done the controlling ground at the wiper switch is removed and the ground in the parking switch keeps the motor running until it reaches the park position and opens the ground connection.  The problem arises when the ignition switch is turned off before the wiper switch is turned off.  The wiper motor will stop wherever it happens to be at the time.  The next time the ignition switch is turned on, the wiper motor will start and drag the blades across that dry and dirty windshield at best, or if stuck will over heat and destroy itself.  If it does not blow the fuse first.  This will happen even if you discover you left the wiper switch on and turn it off before the ignition switch is turned on, due to the ground being supplied by the park switch. This is what causes most Sunbeams to have scratched windshields.

The Fix

  1. We need to insure the wiper motor will always go to the park position whenever the ignition switch is turned off.
  2. We need to insure that the wiper motor won't start if you turn on the ignition switch with the wiper switch still in the on position.
  3. We need intermittent operation to prevent further scratching of windshields when there is only a light mist to obscure your vision.


The Solution - The Cool Cat Wiper Controller