Control Unit Input Test

Driver's Multiplex Control Unit 

• 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 Under-Dash Fuse/Relay Box Socket

  Courtesy of AMERICAN HONDA MOTOR CO., INC.
  Fig 2: Identifying Driver's Multiplex Control Unit Connector B

  Courtesy of AMERICAN HONDA MOTOR CO., INC.
  Fig 3: Identifying Driver's Under-Dash Fuse/Relay Box Connector J

  Courtesy of AMERICAN HONDA MOTOR CO., INC.
  Fig 4: Identifying Driver's Under-Dash Fuse/Relay Box Connector M

  Courtesy of AMERICAN HONDA MOTOR CO., INC.

• 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.
  TEST CONDITION TEST DESIRED RESULT CHART
  
  

  Cavity	Wire	Test condition	Test: Desired result	Possible cause if result is not obtained
  A12	Fuse/relay box socket	Under all conditions	Check for voltage to ground: There should be battery voltage.	Blown No. 13 (7.5 A) fuse in the passenger's under-dash fuse/ relay box Faulty driver's under-dash fuse/ relay box An open in the wire
  A14		Under all conditions	Check for continuity to ground: There should be continuity.	Poor ground (G401) Faulty driver's under-dash fuse/relay box An open in the wire
  B3 B4	ORN/WHT and WHT/RED	Adjusting dial rotated	Check for resistance between the B3 and B4 terminals: There should be 0-20 k ohm as the dial is rotated.	Faulty dash lights brightness controller An open in the wire

• If any test indicates a problem, find and correct the cause, then recheck the system.
• If all the input tests prove OK, the driver's multiplex control unit must be faulty; replace it.
  Fig 5: Test Condition Test Desired Result Chart

  Courtesy of AMERICAN HONDA MOTOR CO., INC.