Control Unit Circuit Test

WARNING: This page is about a different car, the 2010 Infiniti G37. However, it is still accessible from the selected car via links, so may be relevant.

System Description

When the switch is ON, the control unit lights up the lamp.

CASE 1

Fig 1: Identifying Control Unit Circuit Test - Case 1

Courtesy of NISSAN MOTOR CO., U.S.A.

INPUT-OUTPUT VOLTAGE CHART

Terminal No.

Description

Condition

Value (Approx.)

In case of high resistance such as single strand (V) ⁽¹⁾

Signal name

Input/Output

Body ground

Switch

Input

Switch ON

Battery voltage

Lower than battery voltage Approx. 8 (Example)

Switch OFF

0 V

Approx. 0

Body ground

Lamp

Output

Switch ON

Battery voltage

Approx. 0 (Inoperative lamp)

Switch OFF

0 V

Approx. 0

⁽¹⁾	If high resistance exists in the switch side circuit (caused by a single strand), terminal 1 does not detect battery voltage. Control unit does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not supply power to light up the lamp.

The voltage value is based on the body ground.

CASE 2

Fig 2: Identifying Control Unit Circuit Test - Case 2

Courtesy of NISSAN MOTOR CO., U.S.A.

INPUT-OUTPUT VOLTAGE CHART

Terminal No.

Description

Condition

Value (Approx.)

In case of high resistance such as single strand (V) ⁽¹⁾

Signal name

Input/Output

Body ground

Lamp

Output

Switch ON

0 V

Battery voltage (Inoperative lamp)

Switch OFF

Battery voltage

Body ground

Switch

Input

Switch ON

0 V

Higher than 0 Approx. 4 (Example)

Switch OFF

5 V

Approx. 5

⁽¹⁾	If high resistance exists in the switch side circuit (caused by a single strand), terminal 2 does not detect approx. 0 V. Control unit does not detect the switch is ON even if the switch does not turn ON. Therefore, the control unit does not control ground to light up the lamp.

The voltage value is based on the body ground.