Diesel Data: Automotive Repair

Multiplex Control Unit Input Test




Multiplex Control Unit Input Test

NOTE: Before continuing with the multiplex control unit input test, do the multiplex troubleshooting Multiplex Control System Troubleshooting.

1. Remove the driver's dashboard lower cover Driver's Dashboard Lower Cover Removal/Installation.

2. Disconnect under-dash fuse/relay box connectors C, D, F, J, K, O, P, Q, R, X, and Y.

NOTE: All connectors are shown from wire side of female terminals.





3. Inspect the connector and socket terminals to be sure they are all making good contact.

- If the terminals are bent, loose or corroded, repair them as necessary, and recheck the system.
- If the terminals look OK, go to step 4.

4. Reconnect the connectors to the under-dash fuse/relay box, and do the following input tests:

- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, the multiplex control unit must be faulty, replace the under-dash fuse/relay box assembly Under-Dash Fuse/Relay Box Removal And Installation.