Circuit Description
WARNING: This page is about a different car, the 2006 Suzuki Verona. However, it is still accessible from the selected car via links, so may be relevant.
The defogger switch is a momentary switch to ground. The Intelligent Switching Unit (ISU) monitors the status of the defogger switch. The ISU energizes the internal rear defogger relay when it detects a change of status in the defogger switch. The ISU de-energizes the internal rear defogger relay when it detects the next change of status in the defogger switch or a predetermined on time interval has elapsed.