Mercedes MAS Control Unit A0085458532 W124 300E-24 R129 300SL-24 M104 A/C 24V
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Genuine used part
Genuine Mercedes MAS control unit A0085458532 for W124 300 E-24 and R129 300 SL-24 (M104): combines the fuel pump relay and the compressor cut-off control in one unit.
- ✓ Function tested – not an untested salvage part
- ✓ Genuine part – not aftermarket
- ✓ This exact part – photos show the actual item
Condition of this part
Professionally refurbished, tested and fully operational.
Function and location
The MAS combines the fuel pump relay and the compressor cut-off control in one unit: it controls the fuel pumps, the lambda sensor heating, the magnetic clutch of the A/C compressor (including belt slip monitoring), kickdown cut-off, idle speed increase and engine speed limiting, and has its own fault memory.
Important: The rotary knob with I/0 marking on the top is not a switch, but the bayonet lock for the unit bracket.
Installation location: In the engine compartment at the front right, plugged into the bracket and locked with a twist lock; 22-pin connector.
How can you tell that the MAS control unit is faulty?
- Starting problems
- A/C compressor does not engage
- Sporadic misfires
Fits the following Mercedes models
| Model series | Models |
|---|---|
| Mercedes W124/C124/A124/S124 (1989–1993) | 300 E-24, 300 CE-24, 300 CE-24 Cabrio, 300 TE-24, 300 E-24 AMG |
| Mercedes R129 (1989–1993) | 300 SL-24 |
Part numbers: Mercedes-Benz A0085458532 · Mercedes-Benz, successor number (supersedes this part) A 011 545 83 32
⚠ Important: compare the part number before buying
- The exact part number is crucial: There are several similar control units with different last digits. The successor number A 011 545 83 32 supersedes this part. Please compare the number on your old part 1:1.
Does not fit:
- 12V M103 models (300 E/CE/TE, 300 SL – there 007 545 65 32 / 011 545 79 32 / 012 545 46 32)
- 500 SL M119 (011 545 85 32)
- Other M104 version 011 545 82 32 (mostly without A/C)
- From HFM engines (320 models, from approx. 1992/93) – the MAS is dropped entirely there
Related categories: W124
Does this part fit your car? Send us the VIN (chassis number) and model year – we'll check it for free: +49 179 8991069 (Mon–Fri 8 am–6 pm) or via our contact form.
FAQ
Will this part definitely fit my vehicle?
Send us your VIN before you buy. We will check it against the parts catalog and tell you with certainty whether this part fits.
Do I get exactly the part shown in the photos?
Yes. The photos show the actual part you will receive.
Do I need to send in my old part?
No. No core deposit is charged and you don't need to return anything.
KFZTeile-Thot specialises in spare parts for Mercedes classic cars. Free shipping within Germany, 60-day return policy.
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