In the UK, new legislation came into force on March 20th 2013 meaning that MoTs became stricter in relation to airbags. From this date all airbag warning lights (SRS malfunction warning lights) on the dashboard must light up when the ignition is turned on and must go out once the car is started.

This tool is used to assist in the diagnosis of an airbag light being constantly on.
Assists in the diagnosis of a failed air bag unit, failed airbag clock spring and seat-belt pre-tensioners, etc.
Connect in place of the air bag unit to allow the system to test for component failure.
The tool is a 2.5 ohm resistor with two single pin probes, which when connected to the associated wiring effectively become a “dummy” airbag.
Follow all health and safety guidance for airbags.