Multiplex Integrated Control Unit Input Test

1.Remove the left side kick panel (LHD type) or right side kick panel (RHD type).

2.Disconnect the under-dash fuse/relay box connectors D, E, H, I, J, K, N, P and X.

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 4.

4.With the connectors still disconnected from the under-hood fuse/relay box, make these input tests at the connector(s).

  • If any test indicates a problem, find and correct the cause, then recheck the system.
  • If all the input tests prove ok, go to 5.

Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained 
H9 BLK Under all conditions Check for continuity to ground:
There should be continuity. 
  • Poor ground (G601)
  • An open in the wire
 
P1*1
P14*2 		BRN Under all conditions Check for continuity to ground:
There should be continuity. 
  • Poor ground (G502)
  • An open in the wire
 
E9 BLK Under all conditions Check for continuity to ground:
There should be continuity. 
  • Poor ground (G601)
  • An open in the wire
 
D6
·
J9
·
X34 		YEL Ignition switch ON (II) Check for voltage to ground:
There should be battery voltage. 
  • Blown No. 21 (7.5A) fuse in the under-dash fuse/relay box
  • An open in the wire
 
K4 GRN/WHT Under all conditions Check for voltage to ground:
There should be battery voltage. 
  • Blown No. 27 (20A) fuse in the under-dash fuse/relay box
  • An open in the wire
 
X35 WHT Under all conditions Check for voltage to ground:
There should be battery voltage. 
  • Blown No. 7 (10A) fuse in the under-dash fuse/relay box
  • An open in the wire
 
N22 LT BLU Under all conditions Check for continuity between terminal N22 and the climate control unit B (16P) connector terminal No. 14:
There should be continuity. 
  • An open in the wire
 
Climate control unit B (16P) connector disconnected Check for continuity to ground:
There should be no continuity. 
  • Short to ground
 
J4 BRN/RED Under all conditions Check for continuity between terminal J4 and power window master switch 23P connector terminal No. 16:
There should be continuity. 
  • An open in the wire
 
Power window master switch 23P connector disconnected Check for continuity to ground:
There should be no continuity. 
  • Short to ground
 
D11 BLU Under all conditions Check for continuity between terminal D11 and relay module J (10P) connector terminal No. 7:
There should be continuity. 
  • An open in the wire
 
Relay module J (10P) connector disconnected Check for continuity to ground:
There should be no continuity. 
  • Short to ground
 
X27 LT GRN Under all conditions Check for continuity between terminal X27 and wiper/washer switch 8P connector terminal No. 4:
There should be continuity. 
  • An open in the wire
 
Wiper/washer switch 8P connector disconnected Check for continuity to ground:
There should be no continuity. 
  • Short to ground
 
N28 WHT Under all conditions Check for continuity between terminal N28 and gauge assembly (30P) connector terminal No. 25:
There should be continuity. 
  • An open in the wire
 
Gauge control module B (30P) connector disconnected Check for continuity to ground:
There should be no continuity. 
  • Short to ground
 

*1: LHD type 
*2: RHD type 

5.Reconnect the connectors to the under-dash fuse/relay box, and make sure these input tests at the appropriate connectors on the under-dash 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, the multiplex integrated contorl unit must be faulty, replace the under-dash fuse/relay box assembly.

Cavity Wire Test condition Test: Desired result Possible cause if result is not obtained 
P7*1
P8*2 		ORN Under all conditions Attach to ground: The ignition key light should come on. 
  • Blown No. 13 (20A) fuse in the under-hood fuse/relay box
  • Blown LED
  • An open in the wire
 
I4 GRN/RED Ceiling light switch in the middle position, all doors closed Attach to ground: The ceiling light should come on. 
  • Blown No. 6 (7.5A) fuse in the under-dash fuse/relay box
  • Faulty ceiling light
  • An open in the wire
 

*1: LHD type 
*2: RHD type