Mercedes ignition switching unit TSZ-k 0227051024 A0005458432 W116 R107 C107 W114 350 SL
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Ignition switching unit of the contact-controlled transistor ignition TSZ-k, Bosch no. 0 227 051 024 / Mercedes no. A 000 545 84 32, for the W114, W116 and R107/C107.
Genuine removed part · Security lacquer intact – not yet opened · Fits W114, W116, R107/C107
Condition of this part
Used removed part, untested. The aluminium die-cast housing is matte and oxidised throughout, with dark spots and storage dust; no cracks or deformation are visible. The cover sits firmly with a surrounding seal and four yellow-zinc-plated nuts; the red security lacquer on one nut is intact – an indication that the unit has not been opened before. The base plate shows clear scratch and abrasion marks; all three mounting lugs are undamaged. The contacts of the 4-pin connector and the coaxial centre pin are slightly tarnished, but straight and free of verdigris; the coaxial outer contact is slightly corroded on the inside. No functional test was carried out.
Function and location
The TSZ-k switching unit takes the trigger signal from the breaker contact in the distributor and switches the ignition coil's primary current electronically. As a result, the breaker contact only carries a control current, which significantly reduces contact burn and allows a stronger ignition spark.
The unit is installed in the engine bay on the wheel arch or bulkhead, connected via a 4-pin shielded round connector and a single coaxial connection to the ignition coil.
How can you tell an ignition switching unit is defective?
- Engine does not start, or there is no ignition spark
- Rough running engine, misfires, or ignition faults
- The breaker contact in the distributor burns out unusually quickly
Compatible vehicles
W114:
- 280 E
- 280 CE
W116:
- 280 SE, SEL
- 350 SE, SEL
- 450 SE
- 450 SE, SEL
R107 / C107:
- 350 SL
- 450 SL
- 350 SLC
- 450 SLC
Part numbers
Bosch number 0 227 051 024, Mercedes-Benz part number A 000 545 84 32.
⚠ Important: compare the part number before buying
Not to be confused with Bosch 0 227 100 001 (Mercedes A 000 545 76 32) – that is the contactless TSZ-i with inductive sensor. The connectors do fit, but the units are not functionally interchangeable; the engine will not run with it.
Not identical to:
- Bosch 0 227 051 014 (A 000 545 39 32) – earlier version of the same family with cooling fins
- Bosch 0 227 051 015 (A 000 545 41 32) – for the W108, W111, W113, and early W114/W115
- Not a D-Jetronic injection control unit of the 0 280 000 xxx series – significantly larger housing
- Scope of delivery excludes mating connector, cable, and bracket
Does this part fit your car? Send us the VIN (chassis number) and model year – we'll check it for free: 0179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.
FAQ
Is the ignition switching unit tested?
No, this is a used removed part without a functional test. The red security lacquer on one housing nut is intact – an indication that the unit has not been opened before.
How does the TSZ-k differ from the TSZ-i?
The TSZ-i (Bosch 0 227 100 001, Mercedes A 000 545 76 32) is a contactless version with an inductive sensor. The connectors do fit this unit, but the two systems are not functionally interchangeable.
What's included in the scope of delivery?
The switching unit itself; mating connector, cable, and bracket are not included. For further details, see the product photos.
Related categories: W116, W107 / R107
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
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