1999 BMW Z3 Cruise Control Isn't Working

Common Causes of Cruise Control Malfunctions in Your 1999 BMW Z3 and How to Fix Them

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Reviewed by
Bo Fader
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 1999 BMW Z3 cruise control isn't working are failed control module, sensor or switch issues, or throttle actuation problems.
  • Sensor: A faulty or malfunctioning sensor can lead to incorrect readings, causing issues with engine performance or other systems relying on accurate data.
  • Control Module: A faulty control module can lead to 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 throttle 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 1999 BMW Z3 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.

When the vehicle speed sensor fails or the wiring harness prevents signal transmission, the speedometer is the first thing that will stop functioning properly. This can be an intermittent issue where the speedometer only works occasionally, the speedometer may cease all function, or the speedometer may read erratically or incorrectly. Also, the traction control and anti lock brake warning lights specific to each vehicle may be illuminated, depending on the design of those systems. You may notice the vehicle hesitate to accelerate, cruise control will not function properly, and the vehicle may not shift properly through all of the gears.

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.

If the cruise control refuses to turn on at all, the actuator could be at fault. Likewise, if the cruise control stays on but does not maintain a consistent speed, the problem could be a bad actuator. In extreme cases, a malfunctioning actuator could cause the throttle to stick and prevent the vehicle from slowing down. These symptoms may point to a bad actuator. They may also point to other problems with the cruise control and related systems.

The cruise control switch can cause complete failure of the cruise control feature, but in a lucky scenario only partial functionality will be lost. This means that the cruise control may come on, but that it will not increase in speed automatically, or the cancel button does not work leading the driver to cancel cruise control with the foot brake. In some vehicles, the cruise control light may illuminate, or a warning message may be displayed due to lack of functionality.

A faulty cruise control module will simply result in deactivation of cruise control settings. This is because a detected error in the cruise control system could lead to hazardous driving conditions, so the module will be disabled, and the cruise control system warning light will be displayed. This will be a different message depending on make and model, and a warning light or message may be displayed on the driver instrument cluster.

What are the steps to diagnose the cruise control issue in a 1999 BMW Z3?

To effectively diagnose a cruise control issue in a 1999 BMW Z3, start with a systematic approach that prioritizes simpler checks before delving into more complex diagnostics. Begin by inspecting the cruise control buttons to ensure they are functioning correctly and sending the appropriate signals to the engine controller. Next, examine the brake switch, as a malfunction here can prevent the cruise control from engaging or cause it to disengage unexpectedly. Following this, assess the cruise control module for any internal faults that could disrupt its operation. It's also essential to check the wiring harness for any signs of damage or corrosion that might affect connectivity. Finally, utilize a specialized BMW scanner to read fault codes from the vehicle's modules, which can provide valuable insights into any underlying issues affecting the cruise control system. By following this structured diagnostic approach, you can efficiently identify and address the root cause of the cruise control problem.

What are the common problems that could cause the cruise control to stop working in a 1999 BMW Z3?

When dealing with cruise control issues in a 1999 BMW Z3, it's crucial to understand the common problems that may be at play. One of the primary culprits is a malfunctioning speed sensor, which can disrupt the system's ability to maintain speed, rendering the cruise control ineffective. Additionally, the rear brake light switch is known to fail in these vehicles; if this switch is not functioning correctly, it can signal the cruise control to disengage unexpectedly. Another potential issue is a fault within the control module itself, which can lead to various operational problems. For those with adaptive cruise control, it may be beneficial to disable this feature temporarily, as it can sometimes interfere with standard cruise control functionality. By identifying and addressing these common issues, DIYers can restore their BMW Z3's cruise control to proper working order, ensuring a smoother driving experience.

How urgent is it to repair the non-functioning cruise control in a 1999 BMW Z3?

Addressing the non-functioning cruise control in your 1999 BMW Z3 is not just a matter of convenience; it is a critical safety concern that requires immediate attention. A malfunctioning cruise control system can lead to erratic vehicle behavior, making it difficult to maintain control, especially at high speeds. This can significantly increase the risk of accidents, putting both the driver and others on the road in danger. Additionally, the underlying issues that cause cruise control failures, such as faulty sensors or control modules, can lead to more severe mechanical problems if left unresolved. These issues can affect not only the cruise control but also the overall performance and fuel efficiency of your vehicle. Therefore, it is essential to prioritize the repair of your cruise control system to ensure safe driving conditions and to prevent further damage to your BMW Z3.

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