Electrical Load Idle-Up Signal

The Powertrain Control Module (PCM) receives a signal from the diode module when any of the following electrical loads are present:
^ HVAC blower motor
^ Rear window defogger
^ Headlights

The PCM will increase the engine idle speed when receiving the diode module input. The PCM will signal the Idle Speed Control (ISC) motor to activate the ISC motor plunger in order to open the throttle plate. Opening the throttle plate slightly will maintain an engine speed that provides a desirable idle. The PCM will return the engine to the original idle when the diode module signal is removed. The diode module is located under the glove box near the cigarette lighter.