Operating principle of the exterior lighting, turn signal, fog light, and windshield wiper switch
The lever switches for the exterior lighting, turn signal, fog light, and windshield wiper form a single, non-separable unit called the "steering column switch assembly."
This element consists of a single control stage, implemented using diodes and switches.
When certain contacts in the steering column switch assembly are closed, the UCH recognizes the driver's input.
fig. 1. Steering column switch contact connection diagram
Example: the UCH detects the closure of contacts 12 and 14 as a command to turn on the right turn indicators.
Permanent connections 4–3, 12–5, 8–2, 13–14, 10–9 are used to diagnose the steering column switch unit and the connection circuits to the UCH.
Main switch unit faults:
- - fault in the circuit between the switch unit and the UCH;
- - internal electronic fault.
Contact (3) of the black 12-pin connector of the switch unit is connected to contact (14) of the 40-pin connector PE2 of the UCH;
- - contact (4) - with contact (9);
- - (5) — (12);
- - (12) — (15);
- - (2) — (4);
- - (8) — (17);
- - (14) — (11);
- - (13) — (5);
- - (9) - (2);
- - (10) - (19).
These wires must not be damaged and must not short to ground.
Removing the steering column switches
Lock the airbag control unit.
Lock the airbag control unit also unlocks the electric steering column lock.
Fig. Preparing to remove the steering column switches: 1 - hole, 2 - direction of travel.
Insert the screwdriver into hole 1 (Fig. 1).
Pull upwards 2 (Fig. 1).
Fig. Steering Wheel Airbag Connector
Disconnect the steering wheel airbag connectors (as indicated by the arrow in Figure 3) using a screwdriver at the point (see arrow, Figure 2).
Fig. Steering wheel airbag connector locations
Set the wheels to the straight-ahead position.
Fig. Preparing to remove the instrument cluster: 1 - contact disc, 2 - bolt.
Remove the steering wheel mounting bolt, steering wheel, and steering column switch housings.
Before removing the steering column switch assembly, mark its position, ensuring that the "0" mark on the contact disc is aligned with the fixed pointer (see Fig. 4).
Loosen bolt 2 (Fig. 4) securing the contact disc.
Partially release the steering column switch assembly to disconnect the connectors.
Remove the steering column switch assembly.
Installation
Make sure the wheels are in the straight-ahead position and that the contact disc mark is in the "0" position.
Fig. Steering wheel installation feature
The steering wheel hub should fit freely into the splines with guides (see Fig. 5).
Do not damage the spline guides.
The steering wheel mounting bolt should be cleaned after each After removal, it must be replaced.
The steering wheel mounting bolt tightening torque is 44 Nm.