Wiper Circuits for Transports

A popular modification for early Sprites and Midgets is to replace the single speed wiper motor with a dual speed motor from a later model car. While it's relatively easy to wire up a switch for the two speeds, getting the wiper motor to auto park when the switch is turned off can be a little more tricky.


HOW DOES IT WORK

Flicking the toggle switch to the first position (slow operation), power is applied to the relay, closing the contact and supplying power to pin 5 on the wiper motor (via pin 87 and 30 on the relay). The Auto Park connection on the Wiper Motor (pin 2) is not connected to anything while the relay is energized.
Flicking the toggle switch to the second position (fast operation), power is supplied directly to pin 3 on the Wiper Motor. At this point you might expect the relay to turn off, but in fact the relay remains turned on by current leaking back out of pin 5 (slow) of the wiper motor (via pin 30 and 87 of the relay). The Auto Park connection on the Wiper Motor (pin 2) is not connected to anything while the relay remains energized.
Flicking the switch to off, causes the relay to turn off, this connects pin 2 of the Wiper Motor to pin 5 of the Wiper Motor (via pin 87a and 30 of the relay). What I think happens here is that power is connected to pin 4 of the Wiper Motor, this must be internally connected to pin 2 via a switch, which allows us to continue to supply power to the slow pin 5 of the motor until it reaches the park position when pin 2 turns itself off.


TO READ MORE DOWNLOAD IT