2014 - Mazda6 - Body and Accessories

BRAKE LIGHT UNIT INSPECTION

1. Disconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

2. Perform the following procedure:

• Remove the following parts:

• Rear seat cushion (See REAR SEAT CUSHION REMOVAL/INSTALLATION.)

• Rear side seat back (See REAR SIDE SEAT BACK REMOVAL/INSTALLATION.)

• Tire house trim (See TIRE HOUSE TRIM REMOVAL/INSTALLATION.)

• C-pillar trim (See C-PILLAR TRIM REMOVAL/INSTALLATION.)

• High-mount brake light (See HIGH-MOUNT BRAKE LIGHT REMOVAL/INSTALLATION.)

• Fold the rear seat back.

• Remove the rear package trim. (See REAR PACKAGE TRIM REMOVAL/INSTALLATION.)

3. Reconnect the negative battery cable. (See NEGATIVE BATTERY CABLE DISCONNECTION/CONNECTION [SKYACTIV-G 2.5].)

4. Verify that the voltages of each of the terminals are as indicated in the terminal voltage table.

• If the voltage is not as indicated in the table, inspect the parts under Inspection item (s).

• If the system does not work normally even though the parts or related wiring harnesses do not have any malfunction, replace the brake light unit. (See BRAKE LIGHT UNIT REMOVAL/INSTALLATION.)

Terminal voltage list (reference)

Terminal	Signal	Connection	Test condition		Voltage (V)	Inspection item(s)
A	Ground	Body ground	Under any condition		1.0 or less	Body ground
D	Brake light illumination request signal	Rear body control module (RBCM)	Because this terminal is for communication, integrity determination by terminal voltage is not possible.
F	Power supply	STOP 10 A fuse	Under any condition		B+	STOP 10 A fuse Battery
G	High-mount brake light signal	High-mount brake light	Brake pedal depressed		B+	High-mount brake light
			Brake pedal not depressed		1.0 or less
H	Brake light illumination status signal	DSC HU/CM	Brake pedal depressed		B+	DSC HU/CM
			Brake pedal not depressed		1.0 or less
I	Brake switch (No.1 signal) signal	Brake switch (No.1 signal)	Brake pedal depressed		B+	Brake switch (No.1 signal)
			Brake pedal not depressed		1.0 or less
J	Brake light signal	Brake light Rear body control module (RBCM)	Brake pedal depressed		B+	Brake light Rear body control module (RBCM)
			Brake pedal not depressed		1.0 or less