Mercedes-Benz W126 cruise control not working
300 SE380 SE
Why does the W126 cruise control not engage?
Common causes are the brake light switch, fuses, oxidised connections, dried-out capacitors and cracked solder joints on the control unit's circuit board. A fault in the fuel pump relay has also been able to prevent operation.
Where is the W126 cruise control control unit?
It is under the dashboard at the instrument cluster, a clear box about 20x20x3 cm in size. Remove the three screws of the lower trim and the box becomes visible. Beware of the air tube, which may stay attached.
Why do the W126 cruise control and traction control act strangely and the throttle get choked?
Dirty or faulty front wheel sensors can give the traction control false pulses, so the system thinks the car is slipping. The cruise control servo then pushes against the accelerator pedal. Cleaning or replacing the sensors fixes the fault.
Related articles
Mercedes-Benz W126 heater blows only hot airMercedes-Benz W126 heater not heating or heat disappears while drivingMercedes-Benz W126 K-Jetronic cold start injectorMercedes-Benz W126 runs too rich: causes and lambda sensor checkMercedes-Benz W126 fuel pressure regulator and pressuresMercedes-Benz W126 clogged and leaking fuel injectorsMercedes-Benz W126 idle speed and high idleMercedes-Benz W126 auxiliary air valve and idle control valve