System Input Test
NOTE:
On Diamante, use of MUT-II Scan Tool (MB991502) is the only method recommended to check system input.
- Access Data Link Connector (DLC). DLC is located under left side of dash panel, near center console. If scan tool is used, go to next step. If voltmeter is used, go to step 3.
- Turn ignition off. Connect scan tool to DLC. Turn ignition on. If buzzer on scan tool sounds when ignition is turned on, ECU input signal for switch circuit is okay. If circuit is faulty, see WIRING DIAGRAMS .
- Install Diagnostic Trouble Code Check Harness (MB991529) to DLC terminal No. 9 (ETACS-ECU) and terminals No. 4 or 5 (ground). See Fig 1. Connect voltmeter to check harness leads. Voltmeter needle should deflect when each of the following switches is operated:
- Ignition switch turned to ON position.
- Driver and front passenger door switches.
- Headlight switch.
- Front driver or passenger door lock switch.
- Hood switch.
- Trunk light switch.
- Front passenger door key cylinder switch.
- Trunk lid key cylinder switch.
- Assist-ECU.
- If switch or related components are not functioning, the voltmeter will not deflect when switch is activated. Replace the appropriate component or repair circuit as necessary. See WIRING DIAGRAMS .