Checking Inputs Without Scan Tool
Use this procedure if scan tool is not available. Scan tool diagnosis is the preferred method. Connect voltmeter between Electronic Timer Alarm Control System Electronic Control Unit (ETACS-ECU) and ground terminals of Data Link Connector (DLC). See Fig 1 . Monitor voltage readings. Operate ignition switch or open and close doors. If needle on voltmeter swings when switch is switched between off and on or door is opened and closed, input signal for that switch is normal.