Control Unit Input Test

WARNING: This page is about a different car, the 2002 Honda Accord, 2001 Honda Accord, 2000 Honda Accord, 1999 Honda Accord, and 1998 Honda Accord. However, it is still accessible from the selected car via links, so may be relevant.

Before testing exterior light control functions, troubleshoot the multiplex control system (see TROUBLESHOOTING ).
Multiplex Control Unit, Driver's:
Remove the driver's multiplex control unit from the driver's under-dash fuse/relay box.
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.
  
  Fig 1: Identifying Driver's Multiplex Control Unit & Fuse/Relay Box Socket Connector Terminals
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Make these input tests at the connector or 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.
  
  Fig 2: Driver's Multiplex Control Unit Input Test Table
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Multiplex Control Unit, Door:
Remove the driver's door panel, and disconnect the 20P connector from the door multiplex control unit.
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 7.
  
  Fig 3: Identifying Door Multiplex Control Unit Connector Terminals
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
Reconnect the connectors to the unit, and make this input test.
- If a test indicates a problem, find and correct the cause, then recheck the system.
- If all the input tests prove OK, go to step 8.
  
  Fig 4: Door Multiplex Control Unit Test Table
  Courtesy of AMERICAN HONDA MOTOR CO., INC.
If all the input tests prove OK, one of the control units must be faulty. Substitute a known-good control unit for the one that is most likely at fault, then recheck the system. If the system works properly, the original control unit is faulty; replace it. If there is still a malfunction, substitute a known-good control unit for the next most likely unit to be at fault, and recheck. If the system works properly, the original unit is faulty; replace it.