Fitment notes: Battery located under hood on right side; European specification group H8 equivalent
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Every control module on the 1986-1991 Mercedes-Benz 300SE — where it lives, replacement time, and what it takes to program a replacement.
Climate Control Module (KE)2.0 hr R&Rno coding
📍 Behind center dashboard climate control panel
⚠️ Electronic climate control on later models; self-calibrating servo motors, no coding required
Instrument Cluster (IC)1.5 hr R&Rno coding
📍 Dashboard behind instrument panel
⚠️ Electromechanical cluster; odometer transfer required for legal compliance
Transmission Control Unit (TCU)1.5 hr R&Rrelearn only +0.3 hr▸ programming details
📍 Under driver seat or center console area
🔧 Mercedes HHT
⚠️ Electronic control for 4-speed automatic (722.3/722.4); adaptive shift learning requires test drive cycles
Engine Control Unit (ECU)1.2 hr R&Rrelearn only +0.4 hr▸ programming details
📍 Engine compartment, passenger side firewall or under passenger kick panel
🔧 Mercedes HHT or Bosch KTS
⚠️ Bosch KE-Jetronic or early LH-Jetronic; basic adaptations for idle and fuel trim; fault code reading via diagnostic connector
Anti-Lock Brake System Control Unit (ABS)1.0 hr R&Rno coding
📍 Engine compartment, driver side inner fender or firewall
⚠️ Bosch ABS 2 or ABS 2E system; self-calibrating, no coding required
Supplemental Restraint System Control Unit (SRS)1.0 hr R&Rrelearn only +0.2 hr▸ programming details
📍 Center console or under front seats
🔧 Mercedes HHT
⚠️ Introduced mid-1980s on W126; fault code clearing required after replacement; crash data non-volatile
Aftermarket tool coverage varies by software version and vehicle build — treat "aftermarket tool" rows as "usually possible" and verify against your tool maker's coverage list before promising a customer. Spot a wrong location or hour? Tell us — corrections ship fast here.
Size-standard part numbers — verify your connector type before buying. Rear blades are model-specific; check the package's vehicle list.
Fuel economy figures are EPA data via fueleconomy.gov (median across matching trims). Performance figures are compiled estimates for the 1989 Mercedes-Benz 300SE 3.0L I6 and can vary by trim.
🔧 Database maintained under the daily editorial review of Chris Hackleman · Master Technician · 20+ years and Jeff Moore · Master Lexus & Toyota Mechanic · 20+ years.