Table of contents: Constant control ↓ Brake light switch ↓ Adjusting the brake light switch ↓ Checking the brake light switch ↓
Constant control
1. The brake lights in the Audi A4 are powered directly from the positive terminal of the battery (via fuse and brake light switch). This means that they should also light when you press the brake pedal without turning on the ignition.
2. The wall behind the car on the right and left should be illuminated with red light if you press the brake pedal.
3. Or, when driving in a column, check in the rearview mirror whether both brake lights of your car are reflected in the headlight reflectors or in the paintwork of the car behind you.
Brake light switch
The brake light switch (3) is located in the bracket above the brake pedal. It should not be confused with the ventilation valves (1 and 2) of the speed control system. 4 - control unit for the vehicle's departure blocking.
The brake light switch is located in the Audi above the brake pedal and is only accessible after removing the left-hand receiving pocket (Chapter Salon).
When the brake pedal is pressed, the switch pin extends and makes contact with the brake lights.
Adjusting the brake light switch
1. Remove the receiving pocket on the left under the instrument panel (chapter Salon).
2. Press the brake pedal with your hand.
3. Press the brake light switch up firmly in its guide.
4. Now release the brake pedal and pull it back until it stops.
5. Due to this, the brake light switch will straighten itself.
6. Such adjustment is carried out only once during installation of the switch, since after multiple adjustments the switch will not be clamped in the guide reliably enough.
Checking the brake light switch
If both brake light bulbs fail, check to see if the switch is the source of the fault:
1. Disconnect the wire connector on the brake light switch.
2. Close the contacts in the connector with a paper clip or a piece of wire.
3. If the brake lights are now on (although this has not happened before), then the switch is faulty.
Tip: Don't confuse the brake light switch with the switch on the brake pedal from the cruise control system. The latter has an additional connection to the vacuum hose.
(The original article is available on the online resource AUDImanual.ru)