Mercedes fuel pump relay KPR A0035452505 W126 R107 420 500 560 SEL SEC SL
Last one in stock
Couldn't load pickup availability
Verified purchases via eBay · in-house test bench · Read customer reviews
Genuine fuel pump relay (KPR) A 003 545 25 05 for Mercedes-Benz W126/C126 and R107, production stage from 09/1989 with a rev limit at 6000/min.
Genuine relay · Fits W126, C126 & R107 V8 · Production stage from 09/1989
Condition of this part
Used genuine relay, sold untested as no test bench is available for this component. The housing shows dust and storage marks, the labelling is fully legible, and the pins are slightly tarnished. No cracks, no signs of burning.
Function and location
The fuel pump relay switches the electric fuel pumps and the oxygen sensor heater, and only enables both while the engine is turning – if the engine speed signal is absent, delivery is cut off immediately. It also controls the cold-start enrichment via the cold start valve and limits engine speed by switching off fuel delivery at 6000/min.
The relay is installed in the relay box in the engine bay, under the cover on the bulkhead. On the W126 and C126, it sits on the driver's side next to the overvoltage protection relay and the A/C relay.
How can you tell if a fuel pump relay is faulty?
- The fuel pump does not start – the engine does not start, or stalls again immediately
- The cold start valve receives no signal – noticeably harder cold starts
- Lambda sensor heater has no power
Compatible vehicles
Mercedes-Benz W126 / C126 S-Class, V8 M116 and M117, production standard from 09/1989, rev limit 6000/min:
- 420 SE, 420 SEL (126.034, 126.035)
- 420 SEC (126.043)
- 500 SE, 500 SEL (126.036, 126.037)
- 500 SEC (126.044)
- 560 SE, 560 SEL (126.038, 126.039)
- 560 SEC (126.045)
Mercedes-Benz R107 SL, V8 models from model year 1985:
- 420 SL (107.047)
- 500 SL (107.046)
- 560 SL (107.048)
Original part number A 003 545 25 05 (KPR, production standard from 09/1989). This number retroactively replaces the earlier versions 003 545 01 05 and 002 545 16 05.
⚠ Important: compare the part number before buying
This number is the production standard from 09/1989 and retroactively replaces the predecessors 003 545 01 05 and 002 545 16 05. Please compare the number on your old relay and the pin count 1:1 – this relay has ten occupied pins in a 12-pin housing.
Does not fit:
- 6-cylinder W126 260 SE, 300 SE, 300 SEL – there 002 545 15 05, 002 545 27 05, 002 545 51 05, 002 545 52 05
- Early square relays of the W126 from 09/1979 to 08/1985 (001 545 07 05, 001 545 16 05, 001 545 05 05, 001 545 34 05)
- W124 and W201 – there 003 545 24 05 and 003 545 19 05
- Overvoltage protection relay and kickdown/A/C relay 003 545 56 05 despite similar design
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 this relay new or used?
This is a used genuine relay. It is sold untested, as no test bench is available for this component; the housing shows dust and storage marks, the pins are slightly tarnished, but there are no cracks or scorch marks.
Does the relay also fit the 6-cylinder W126 or early model years?
No. The 6-cylinder W126 (260 SE, 300 SE, 300 SEL) requires different numbers (including 002 545 15 05, 002 545 27 05). The early square relays of the W126 from 09/1979 to 08/1985 are also different versions (including 001 545 07 05).
Can I replace the relay myself?
The relay is located in the relay box in the engine bay; on the W126 and C126 it sits on the driver's side next to the overvoltage protection and A/C relays. If unsure, we recommend having it replaced by a specialist.
Related categories: Relays · W126 · W107 / R107
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
Share
