The seat belt pretensioner deployment system can be diagnosed.
The seat belt pretensioners are located on the roller mechanisms of the front belts. The driving device pushes up the piston, which is connected through a metal cable with the axis of the belt roller mechanism. Thus, the belt is tensioned on the body with a force of 1200 N, preventing the belt from loosening in an accident. Airbags and seat belt pretensioners are powered by a gas produced in Mercedes vehicles from a solid explosive.
If the electronic triggering device (in front of the gear lever) recognizes a delay of the car, which is identical to a blow at a speed of 15–18 km / h on a solid obstacle, current is applied to the squib cartridges and gas is formed under the action of the explosive process. The system is self-powered by a capacitor, which supplies current to the gas generator squibs even if the battery fails on impact.
SRS warning lamp
The permanent functional readiness of the system is checked by its own monitoring system. When the ignition is switched on, the control lamp lights up for a few seconds and then should go out. If this does not happen or it lights up while the car is moving, there is a malfunction in the system.
Warnings! Airbags, seat belt pretensioners and do-it-yourself repairs
There are strict rules for the transportation, storage of airbags and the organization of the workplace where they are removed and installed. The fact is that a gas generator, which, by setting in motion the solid explosive contained in it in the event of an accident and filling the pillow in a fraction of a second, falls under the law on explosives. In this regard, even with serial installation in production, only specially trained specialists at the workshop are involved, airbag repair mechanics have special qualifications. Given the above, we strongly recommend that you refuse any self-repair of the driver or passenger airbag. This also applies to tuning, when, for example, the steering wheel is trimmed with wood or leather. In any case, work on airbags must only be carried out by a workshop.
The front seats of the Mercedes are equipped with seat belt pretensioners that are activated in the event of an accident. The pretensioners are triggered by a gas generator activated by current. Self-repair of this system is prohibited. Installation and removal of pretensioners must be carried out by workshops under strict safety requirements.
Warning! Caution when working under the vehicle
When performing body work, it is not allowed to use an impact screwdriver or hammer in the area of \u200b\u200bthe roller mechanisms of the seat belts without special care - the pretensioners are very sensitive to vibrations and shocks and can work. Therefore, for safety, before starting work from below the car, it is recommended to remove the pretensioner fuse and wait 5 minutes until the capacitors are discharged.
After an accident, check the system and replace the airbag and front seat belts if necessary.
When installing the system, removing the steering wheel or welding, always remember: the parts of the airbag system must not reach temperatures above +100°C.
Always place the elements of the driver's airbag system on a soft cloth and never leave them unattended.
In addition, they are sensitive to shock. If dropped to the floor from a height of 50 cm or more, they are no longer suitable for further use.