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🟩 1990–1993 Mercedes-Benz 300E 300SE MAS Control Unit — OEM
Part Number: A 007 545 65 32 (0075456532)
Common Name: MAS Relay / Multi-Function Control Unit
Functions: Fuel Pump Relay • Kickdown Control • A/C Compressor Cut-off • Oxygen Sensor Heating
Vehicle Removed From: 1991 Mercedes-Benz 300E (W124)
Condition: Tested • 30 Day Warranty • Free Returns
🔧 Item Description
Genuine Mercedes-Benz OEM MAS Control Unit.
Fits W124 and W126 models equipped with the M103 engine during the 1990–1993 production window.
The MAS (Motor-Aggregat-Steuerung) unit is a "master relay" that consolidates several vital functions into one module, including fuel pump operation and engine speed signal processing.
Removed from a functional donor vehicle that exhibited zero stalling or starting issues.
✅ Functionality & Testing
✔️ Fuel Pump Circuit: Tested for consistent voltage delivery to the fuel pump; verified the pump primes correctly upon ignition.
✔️ Engine Speed Signal: Verified the unit correctly processes the RPM signal for stable engine operation and kickdown functionality.
✔️ A/C Cut-off: Tested the compressor engagement logic to ensure correct behavior under load.
✔️ Internal Inspection: Inspected for the common failure points in vintage Mercedes relays, including heat-stressed solder joints and leaking capacitors.
✔️ Electrical: The multi-pin base is clean, with straight pins and no signs of thermal melting or corrosion.
🧼 Condition & Inspection
Professionally inspected and cleaned.
Housing: The plastic casing is intact, featuring the original Mercedes-Benz and Bosch branding. The locking lever mechanism operates smoothly for a secure fit into the base socket.
Environmental Seal: The unit shows no signs of moisture intrusion or internal oxidation.
🚗 Vehicle Compatibility Mercedes-Benz 300-Series (W124)
1990–1993 300E 3.0 / 300CE / 300TE Mercedes-Benz S-Class (W126)
1990–1991 300SE / 300SEL
⚠️ Fitment Note: This unit is a direct replacement for part number 007 545 65 32. Please ensure your current module uses the round-pin MAS socket configuration before purchasing.
⚙️ Features & Benefits
OEM Reliability: Restores the factory safety logic for fuel delivery and engine management that aftermarket relays often fail to replicate.
Direct Plug-and-Play: No coding or programming required. Simply seat the unit and lock the lever to restore functionality.
Solves Common Issues: Essential for fixing "Crank/No Start" conditions, intermittent stalling, or A/C compressor non-engagement.
🛡️ Warranty & Returns
✔️ 30 Day Warranty — Guaranteed electronic and relay functionality.
✔️ Free Returns — Shop with total confidence.
✔️ Professionally Tested