1990 Mercedes-Benz 300E Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 1990 Mercedes-Benz 300E and How to Fix Them

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Reviewed by
Devin Cabugcal
Written by RepairPal Car Genius
Updated January 14, 2025
0%
30% chance it's the
Sensor
0%
25% chance it's the
Control Module
0%
25% chance it's the
Throttle
0%
20% chance it's
Something else
The most common reasons a 1990 Mercedes-Benz 300E cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty sensor can lead to incorrect readings, causing issues with engine performance or triggering warning lights on the dashboard.
  • Control Module: A faulty control module can result in erratic vehicle behavior or failure of various electronic systems due to improper signal processing.
  • Throttle: A faulty throttle body or a defective accelerator pedal position sensor may be causing inconsistent acceleration and poor engine response.
Proper diagnosis will determine the exact cause of your symptom, saving you money on unnecessary repairs. The diagnostic experts at RepairPal Certified shops have the right tools and experience to solve any symptom.

How much does it cost to fix a 1990 Mercedes-Benz 300E cruise control isn't working?

Common Repairs

The total repair cost will vary based on the condition of your vehicle and the number of repairs needed to fix your symptom. Proper diagnosis will save you money by finding the exact repairs needed to fix your car right the first time.

In the event that a wheel speed sensor fails, the ABS, traction control system (TCS) and manufacturer specific stability control system lights will illuminate, informing the driver that the systems are disabled. The vehicle will be more prone to tire slip, and normal driving patterns may need to be adjusted to correct for the loss of computer control. On older vehicle's, the speedometer can be affected, causing illumination of the check engine light as well.

How urgent is it to repair the non-functioning cruise control in a 1990 Mercedes-Benz 300E?

When assessing the urgency of repairing the non-functioning cruise control in your 1990 Mercedes-Benz 300E, it's essential to consider how much you rely on this feature for your driving experience. If your cruise control issues stem from minor problems like a blown fuse or a faulty brake switch, the repair may not be immediately critical, as these do not typically pose safety risks. However, neglecting these symptoms could lead to more significant issues down the line, such as further electrical failures or complications with the vehicle's braking system. On the other hand, if the malfunction is due to a failed control module or a malfunctioning cruise control amplifier, addressing these problems sooner can prevent potential damage to other components and ensure that your vehicle operates smoothly. Ultimately, if you frequently take long drives or depend on cruise control for comfort during commutes, prioritizing the repair is advisable. Conversely, if you can manage without it, you might choose to delay the repair until it becomes more convenient.

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1990 Mercedes-Benz 300E Cruise Control Issues & Repair Guide