Mercedes fuel pump relay A0025453305 W126 420 500 560 SEC SEL R107 420 SL
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Genuine fuel pump relay A0025453305 for Mercedes-Benz W126 420, 500 and 560 SE/SEL/SEC as well as R107 420 SL and 500 SL.
Genuine component · Housing intact, labeling legible · Fits W126 06/1985–06/1987 and R107 from 1986
Condition of this part
Used genuine relay, sold untested as no test bench is available. Housing intact, labeling fully and clearly legible. The contact pins have a brass patina; slight verdigris traces show between two pins – clean before installation. Residual potting compound on the base rim, no rust, no cracks.
Function and location
The relay switches the electric fuel pumps together with the lambda sensor heater and only enables them as long as an engine speed signal is present – if the engine stops, fuel delivery is switched off immediately. It also limits engine speed at 6000/min and links the cutoff via the kickdown circuit to the automatic transmission control. The housing print reads 8 Zyl., 6000/min, KVS, Kickd.
It is installed in the engine bay on the passenger side, under the plastic cover of the relay box behind the battery, directly next to the overvoltage protection relay.
How can you tell if a fuel pump relay is faulty?
- Fuel pump does not start running, engine does not start or starts only with difficulty
- Engine suddenly dies at idle or under load
- Lambda sensor heater remains non-functional, warm-up behavior deteriorates
- Engine speed is not limited at 6000/min, or is limited irregularly
- Automatic transmission kickdown does not shift cleanly
Compatible vehicles
Mercedes-Benz W126 / C126 S-Class, V8 M116 and M117, 06/1985–06/1987:
- 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, model year from 1986:
- 420 SL (107.047)
- 500 SL (107.046)
Part numbers at a glance: Main number A0025453305, valid 06/1985–06/1987. Successor versions: 002 545 16 05 (from 08/1987, lowered temperature threshold), 003 545 18 05, 003 545 01 05 and 003 545 25 05. For other engine variants: 001 545 91 05 and 002 545 27 05 (6-cylinder), 002 545 20 05 (4-cylinder, 6200/min), 003 545 56 05 (W124 A/C/kickdown relay), 001 545 34 05 and 001 545 04 05 (early 8-cylinder versions).
⚠ Important: compare the part number before buying
The final number is decisive. This version covers the period 06/1985 to 06/1987. From 08/1987, 002 545 16 05 followed with a lowered temperature threshold, along with 003 545 18 05, 003 545 01 05 and 003 545 25 05. Please compare the print on your old relay 1:1 – 8 Zyl. and 6000/min must match.
Does not fit:
- 6-cylinder vehicles – there 001 545 91 05 and 002 545 27 05
- 4-cylinder vehicles – there 002 545 20 05 with 6200/min
- 380 SE, 380 SEL, 380 SEC and 380 SL before 06/1985
- W124 A/C and kickdown relay 003 545 56 05
- Early 8-cylinder relays 001 545 34 05 and 001 545 04 05
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
What's included in the scope of delivery?
The exact scope of delivery is shown in the product photos.
How do I know if this relay fits my vehicle?
Compare the print on your old relay with “8 Zyl., 6000/min, KVS, Kickd.”. This version applies to the period 06/1985 to 06/1987; different end numbers were used afterward. If unsure, send us the VIN and model year for a free check.
Was the relay tested for function?
No, it is sold as a used genuine relay, untested, as no test bench is available. Visually the condition is good: housing intact, labeling fully legible, no cracks; the contact pins should be cleaned before installation.
Related categories: Relays · W126 · W107 / R107
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
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