Headlamp Alignment Sensor: Service and Repair

Vehicle "level" sensor in vehicles with automatic headlight range control





Vehicles with gas discharge lights have an automatic headlight range control.

The automatic headlight range control requires information on front and rear axle suspension spring compression and extension to function.

Therefore the altitude (inclination) of the left lower link in relationship to the body is passed to the vehicle left front level control system sensor -G78- via a connecting link. The sensor passes the signals onto the headlight range control, control module.

On the rear axle the signals are passed to the control module by the vehicle left rear level control system sensor -G76-.

These signals are required to determine the inclination of the vehicle.

The automatic headlight range control reacts automatically to changes in the vehicle inclination.

The vehicle inclination can change with the following situations;

^ Towing a trailer
^ Various load conditions: Vehicle empty, vehicle partially or fully loaded
^ Driving slowly or very fast

WARNING:
Headlight adjustment!

Checking the headlight basic setting must always be carried out when:
^ The link/arm is removed and installed or replaced.

^ Work is performed on vehicle "level" sensor
^ Vehicle "level" sensor is replaced
^ Coupling rod retaining clip on link/arm has been loosened.

Headlight basic settings

Refer to Powertrain Management; Self-diagnosis of automatic headlight range control; Basic setting

1. Bracket
2. Hex nut, 8 Nm (70.1 inch lbs.)
3. Vehicle left front level control system sensor -G78-
^ Checked electrically via self-diagnosis
^ When complaints are received

Refer to Powertrain Management; Self-diagnosis of automatic headlight range control

4. Connecting link from vehicle left front level control system sensor-G78

^ Bolt the connecting link tightly in area of marking on bracket - 9 - arrow
5. Semi-trailing arm
6. Hex bolt, 45 Nm (33 ft. lbs.)
7. Coupling rod
8. Hex nut, 4 Nm (35.4 inch lbs.)
9. Bracket
10. Anti-roll bar
11. Connector
12. Longitudinal member
13. Pop rivet screw

You can install pop rivet screw with the pop rivet pliers VAG 1765 B.