Exterior Lights (MICU) Input Test
NOTE:
If you are troubleshooting multiple DTCs, be sure to follow the instructions in B-CAN System Diagnosis Test Mode A.
Before testing, make sure the No. B1 (20 A), No. B19 (15 A), No. B21 (15 A), No. B29 (10 A), No. B32 (10 A), and No. B33 (10 A) fuses in the under-hood fuse/relay box are OK.
Before testing, make sure the No. C15 (10 A), C29 (10 A), and No. C34 (7.5 A) fuses in the under-dash fuse/relay box are OK.
Before testing, make sure the No. D1-5 (30 A) and No. D9 (10 A) fuses in the auxiliary under-dash fuse box are OK.

1.
Turn the vehicle to the OFF (LOCK) mode.

2.
Disconnect under-dash fuse/relay box connectors B, D, H, N, Q, R, and T.

NOTE: All connector views are shown from the wire side of the female terminals.
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 are OK, go to step 4.

4.
With the connectors still disconnected, do the following input tests:
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.

Cavity
Wire
Test condition
Test: Desired result
Possible cause if desired result
is not obtained
Q38
LT BLU
Under all conditions
Connect terminal to ground with a jumper wire:
The left headlight (low beam) should come on.
Faulty headlight low beam relay
Blown bulb
Poor ground (G302) or an open in the ground wire
An open or high resistance in the wire
Connect terminal to ground with a jumper wire:
The right headlight (low beam) should come on.
Faulty headlight low beam relay
Blown bulb
Poor ground (G202) or an open in the ground wire
An open or high resistance in the wire
Q17
·
R1
PUR
·
RED
Under all conditions
Connect terminals Q17 and R1 with a jumper wire:
The left headlight (high beam) should come on.
Blown bulb
Poor ground (G301) or an open in the ground wire
An open or high resistance in the wire
T2
·
R1
ORN
·
RED
Under all conditions
Connect terminals T2 and R1 with a jumper wire:
The right headlight (high beam) should come on.
Blown bulb
Poor ground (G202) or an open in the ground wire
An open or high resistance in the wire
T16
LT GRN
Under all conditions
Connect terminals T16 and ground with a jumper wire:
The right front parking light and right front side marker light should come on.
Blown bulb(s)
Poor ground (G202, G302, G503, G504) or an open in the ground wire
An open or high resistance in the wire
Q37
GRY
Under all conditions
Connect terminal to ground with a jumper wire:
The fog lights should come on.
Blown No. B19 (15 A) fuse in the under-hood fuse/relay box
Blown bulb(s)
Faulty fog light relay
An open or high resistance in the wire

5.
Reconnect the connectors to the under-dash fuse/relay box, do the following input tests:
If any test indicates a problem, find and correct the cause, then recheck the system.
If all the input tests prove OK, the MICU must be faulty; replace the under-dash fuse/relay box.

Cavity
Wire
Test condition
Test: Desired result
Possible cause if desired result
is not obtained
Q15
RED
Under all conditions
Measure the voltage to ground:
There should be battery voltage.
Blown No. B29 (10 A) fuse in the under-hood fuse/relay box
An open or high resistance in the wire
R1
RED
Under all conditions
Measure the voltage to ground:
There should be battery voltage.
Blown No. D1-5 (30 A) fuse in the auxiliary under-dash fuse box
An open or high resistance in the wire
D23
BLK
In all power modes
Measure the voltage to ground:
There should be less than 0.2 V.
Poor ground (G401)
An open or high resistance in the ground wire
H1
BLK
In all power modes
Measure the voltage to ground:
There should be less than 0.2 V.
Poor ground (G401)
An open or high resistance in the ground wire
N6
BLK
In all power modes
Measure the voltage to ground:
There should be less than 0.2 V.
Poor ground (G501)
An open or high resistance in the ground wire
N38
BLK
In all power modes
Measure the voltage to ground:
There should be less than 0.2 V.
Poor ground (G501)
An open or high resistance in the ground wire
B4
·
B10
BRN
·
BLK
Combination light switch OFF
Measure the voltage between terminals B4 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Combination light switch in any position other than OFF
Measure the voltage between terminals B4 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire
B5
·
B10
GRY
·
BLK
Combination light switch (PARKING position) ON
Measure the voltage between terminals B5 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Combination light switch OFF
Measure the voltage between terminals B5 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire
B11
·
B10
WHT
·
BLK
Combination light switch (headlight) ON
Measure the voltage between terminals B11 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Combination light switch OFF
Measure the voltage between terminals B11 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire
B12
·
B10
RED
·
BLK
Combination light switch lever pulled (Passing)
Measure the voltage between terminals B12 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Combination light switch lever released (OFF)
Measure the voltage between terminals B12 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire
B3
·
B10
YEL
·
BLK
Combination light switch (Dimmer) in high beam position
Measure the voltage between terminals B3 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Combination light switch (Dimmer) in low beam position
Measure the voltage between terminals B3 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire
B13
·
B10
PUR
·
BLK
Fog light switch ON
Measure the voltage between terminals B13 and B10:
There should be less than 0.2 V.
Faulty combination light switch
An open or high resistance in the wire
Fog light switch OFF
Measure the voltage between terminals B13 and B10:
There should be about 5 V.
Faulty combination light switch
A short to ground in the wire