Wiper Cir Cut

Intermittent wiper controller. On-off switch 500k

47k

+12 VDC on wiper switch

10k

2N4403

2N4401 100k

+

Normally open contacts

3.3k To wiper moter

100 uf

12 volt relay 1N4002

The intermittent wiper circuit shown above causes the auto's windshield wipers to wipe once every several seconds instead of constantly wiping. The circuit may be added to older cars to provide the intermittent function or it may be used to replace broken wiper circuits in modern cars. The delay is continuously adjustable with the potentiometer but switch selected fixed resistors may also be used, if desired. The circuit should be connected to +12 volts at the same point as the original wiper power switch so that the proper fuse protection is preserved. The 12 volt relay should have contacts rated for a few amps since the wiper motor will draw a considerable start current but most automotive relays are adequate. The circuit should be quite trouble-free and will work on the first try if no wiring errors are made!