Control Unit Input Test
Control Unit Input Test1. Before testing the dash lights brightness control functions, troubleshoot the multiplex control system.
Driver's Multiplex Control Unit:
2. Remove the driver's multiplex control unit from the driver's under-dash fuse/relay box.
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 OK, go to step 4.
4. With the control unit still disconnected, make these input tests at the connector and fuse/relay box socket.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK go to step 5.
5. Reconnect the driver's multiplex control unit to the fuse/relay box, and perform the following input tests at the appropriate connectors on the back of the fuse/relay box.
- If any test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 6.
6. If all the input tests prove OK, the driver's multiplex control unit must be faulty. Substitute a known-good control unit, then recheck the system. If the system works properly, the original control unit is faulty; replace it.