Multiplex Control Unit Tests

1. Remove driver's multiplex control unit from driver's underdash fuse/relay box. Disconnect security control unit connectors. Inspect connectors and terminals. Check for bent, loose or corroded terminals. Perform driver's multiplex control unit input tests. See Fig 1 . Repair as necessary and recheck system operation. If driver's multiplex control unit inputs are okay, go to next step.
2. Reconnect driver's multiplex control unit to underdash fuse/relay box. Perform input tests as specified at back side of fuse/relay box (backprobe). See Fig 2 . Repair as necessary. If all tests are okay, go to next step.
3. Remove passenger's multiplex control unit from passenger's underdash fuse/relay box. Disconnect 22-pin connector. Inspect connectors and terminals. Check for bent, loose or corroded terminals. Perform passenger's multiplex control unit input tests. See Fig 3 . Repair as necessary and recheck system operation. If passenger's multiplex control unit inputs are okay, go to next step.
4. Reconnect passenger's multiplex control unit to underdash fuse/relay box. Perform input tests as specified on passenger's fuse/relay box connectors. See Fig 4 . Repair as necessary. If all tests are okay, go to next step.
5. Remove driver's door multiplex control unit (built into power window switch). Disconnect 20-pin connector. Inspect connectors and terminals. Check for bent, loose or corroded terminals. Perform driver's door multiplex control unit input tests. See Fig 5 . Repair as necessary and recheck system operation. If driver's door multiplex control unit tests are okay, go to next step.
6. Reconnect driver's door multiplex control unit connector. Perform tests as specified by backprobing connector. See Fig 6 . Repair as necessary. If all tests are okay, go to next step.
7. If all tests have proven okay, substitute a known-good control unit for unit most likely at fault. Recheck system operation. If system operates properly, replace original control unit. If system still malfunctions, replace next most likely unit to be at fault and recheck system operation. Repeat procedure until malfunction no longer exists.

Fig 1: Driver's Multiplex Control Unit Test (1 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 2: Driver's Multiplex Control Unit Test (2 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 3: Passenger's Multiplex Control Unit Test (1 Of 2)

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Fig 4: Passenger's Multiplex Control Unit Test (2 Of 2)

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Fig 5: Driver's Door Multiplex Control Unit Test (1 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.

Fig 6: Driver's Door Multiplex Control Unit Test (2 Of 2)

Courtesy of AMERICAN HONDA MOTOR CO., INC.