Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
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HOMESERVICE MANUALSMERCEDES BENZ1989420SELREPAIR AND DIAGNOSIS (SINGLE PAGE)QUICK LOOKUPSELECTRICAL COMPONENT LOCATIONSELECTRICAL COMPONENT LOCATORCONTROL UNITS
1989 Mercedes Benz 420SEL
Control Units
1989 Mercedes Benz 420SELSECTION Control Units
CONTROL UNITS LOCATION
| Component | Location | |
|---|---|---|
| ABS Electronic Control Unit | On right rear corner of engine compartment. See Figure. | |
| A/C Compressor Control Unit | ||
| 420 & 560 SEL | Above right side of passenger's footwell. See Figure. | |
| 560 SEC | On left rear side of engine compartment. See Figure. | |
| A/C Control Unit | Above right side of passenger's footwell. See Figure. | |
| Anti-Theft Control Unit | On right side of blower housing. See Figure. | |
| CIS-E Fuel Injection Control Unit | ||
| Top View | Above right side of passenger's footwell. See Figure. | |
| View of Control Unit | Above right side of passenger's footwell. See Figure. | |
| View From Passenger Compartment | Above right side of passenger's footwell. See Figure. | |
| Cruise Control Amplifier | Above right side of driver's footwell. | |
| Cruise Control Unit | Above right side of passenger's footwell. | |
| Electronic Illumination Control Unit | Under left side of dash. | |
| Electronic Blower Control Unit | In blower housing. | |
| Idle Speed Control Unit | Under passenger side floorboard. See Figure. | |
| Ignition Switching Control Unit | On left front inner wheelwell. | |
| Key/Light Warning Module | Above left side of driver's footwell. | |
| Oxygen Sensor Control Unit | On right side of passenger's footwell. | |
| Seat Adjustment Control Unit | Under both front seats. | |
| Seat Back Warning Module | On left side of driver's footwell. | |
| Seat Belt Modules | Behind rear seat side panels. | |
| SRS Control Unit | On right side of blower housing. See Figure. | |
| Transmission 1st Gear Control Unit | Under dash, above accelerator pedal. | |
RENDER: 1.0x
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.