ICl is connected in the astable mode, driving RLA, C3, Dl, and D2 prevent spikes from the relay coil and the wiper motor from triggering ICl. VR2 is adjusted to give the minimum delay time required. VR1 is the main delay control and pro vides a range of from about 1 second to 20 seconds. SW1 is an override switch to hold RLA permanently on (for normal wiper operation)
The relay should have a resistance of at least 150 ohms and have heavy duty contacts. The suppression circuit may be needed for the protection of ICl.