Airbag control unit with part number 003 820 73 10

What does the airbag control unit 003 820 73 10 do?

The airbag control unit 003 820 73 10 is the control module of the SRS system in the Mercedes-Benz SL R107 built from 1985 to 1989. It evaluates the crash sensor and fires the driver airbag and the belt tensioners in a frontal collision. The manufacturer is Bosch; the Bosch number 0 285 001 014 is also printed on the housing.

The unit sits in an aluminium housing and belongs to the first generation of Mercedes airbag control units, whose sister units from the 003 820 xx 10 range work in the S-Class W126 and the W124. It monitors the firing circuits, the vehicle voltage and its own energy reserve, and reports faults via the SRS warning lamp.

Why does the control unit 003 820 73 10 fail?

The failures are age-related: dried-out electrolytic capacitors in the energy reserve, cold solder joints from vibration and temperature cycles, and corroded contacts on the connector. After an accident with deployment the unit also stores crash data and locks itself.

Typical is an SRS lamp that stays on permanently or only comes on after a few minutes of driving, once the electronics warm up. The workshop tester then often can no longer connect to the control unit.

Which vehicles use the control unit 003 820 73 10?

Part number 003 820 73 10 belongs to the Mercedes-Benz SL R107 with driver airbag, which was available as an option from the 1985 facelift onwards – above all the 300 SL, 420 SL, 500 SL and 560 SL up to 1989.

The same number is also found in other Mercedes models of those years, such as the W124 and the W201 (190 series). You can see whether your unit carries this number on the aluminium lid directly below the Bosch lettering.

How does the repair at Airbag24 work?

You send the removed control unit to Airbag24, we test it on the bench, replace aged components, rework solder joints and erase stored crash data. The repaired original unit is usually returned after 3–4 working days and is refitted without any further adaptation.

Airbag24 has been repairing airbag control units for more than 20 years – over 20,000 units, TÜV-safe. Since new units for the R107 are hardly available any more, repairing the original unit is the usual way to bring the SRS system back into service. You will find the repair types and the order on the product page Mercedes-Benz SL-Class R107 Convertible airbag control unit repair.