Actuator Clicking When Car Is Off. What's This and How to Fix?

A clicking noise when the car is off can be disconcerting, to say the least. You will hear from seasoned drivers and mechanics that actuators make such clicking sounds. In most situations, you should be concerned when you hear a clicking sound and should work to resolve the problem as soon as possible. While some actuator clicking sounds can be alarming, in most cases, the problem can easily be resolved.

Relay problems highlights

• Level of urgency:low
• DIY inspection:possible but complicated
• DIY repair:possible
• Can you drive?yes
• Price for repairs:$20 - $250
• Symptoms:certain functions may not work, clicking sound
• Ways to solve:replace the faulty relay

What are actuators, and how do they work?

Almost all car functions are made possible by actuators. Actuators are the behind-the-scenes workers that make a car function the way it does. Actuators are usually small in size and are mandated with converting energy, mostly electrical, into some force or physical action. Actuators are responsible for functions such as climate control, tailgates, throttle, and so many more.

You will see that most actuators are either electrically powered or mechanically powered using some fluid pressure or airflow. These actuators are controlled by microprocessors and will take commands from you directly or from the computer.

Closing the sunroof requires you to give a command, for example. On the other hand, when you depress the accelerator, the ECU reads the pedal's position and electronically commands the throttle actuator, allowing more airflow into the engine. Lane centering, assisted braking system, and variable valve timing are some of the crucial areas where actuators play a central role.

Reasons why the actuator clicks when the car is off

When you turn off the engine, you might hear a clicking sound in the dashboard. Sometimes, this might not alarm you, but there is good reason to be concerned. Finding the reason behind this clicking sound can be easy, but in most cases, it has proven to be tricky and engaging, and that's why you need a professional to help you solve the problem.

1) Faulty blend door actuator

The leading cause of the clicking noise in the dashboard when the car is off is the blend door actuator going bad. The blend door actuator is a tiny HVAC motor that works hand in hand with the temperature sensors in the car to regulate the climate control system. When you want cool or warm air in the car, you are actually communicating with the blend door actuator. The actuator controls which vents in the car the air will come from. Newer cars that have front and rear climate controls have two blend door actuators.

The leading symptom of the blend door actuator failing is a clicking noise when the car is off. This clicking is incessant and originates from below the dashboard. In other instances, you might hear as though someone is knocking on the door. This is experienced right after you start the engine, but it's not as common as the clicking noise.

Solution

You should take your car to a professional to help you solve this problem. If you have some experience in car mechanics and have a calibrator with you, then follow these steps. You will also need to buy a new blend door actuator before you start.

• Disconnect the negative terminal on your battery.
• Remove the glove box by pulling it off its retaining knobs.
• Unplug the wiring harness and find the heater core, normally found right behind the glove box.
• Remove the filter assembly, which then gives you room to remove the door actuator.
• Test whether the blend door is working properly by physically rotating it in both directions. This helps in ensuring the door is working as expected and doesn't cause damage to the new actuator.
• Install the new actuator.

2) Faulty relay

Your car has numerous relays, most of which are located under the hood. You may also find relays inside the cabin near the glove box. When a relay goes bad, you are likely to hear clicking sounds even when the car is off. The noise is made when the relay engages and disengages. You may need to listen carefully to your car to know the source of the clicking sound or use an OBD-II scanner to know which relay is faulty.

Solution

Solving a relay problem is easy and relatively cheap. You will need to buy a replacement and install it. However, you should read the relay and fuse map on the cover to ensure you buy the correct replacement. You can actually replace a relay by yourself.

3) The HVAC system is uncalibrated

The HVAC system relies on the HVAC module, which controls a plethora of sensors, motors, and actuators. When the HVAC system is uncalibrated, the sensors will pick the wrong figures, leading to the module miscalculating the position of the motors. A clicking sound will be heard when the motor and the actuators work with the wrong readings.

Solution

The answer to this problem lies in calibrating the HVAC system again. Here are the steps to follow to resolve this issue;

• Turn the ignition to 'ON.'
• Press the 'auto' button for the climate control system.
• Turn the ignition to 'OFF.'
• Disconnect the HVAC fuse for one minute and then switch 'ON' the engine. Leave the ignition in the ON position for two minutes. This resets the HVAC system. It is imperative that you tend to the problem as soon as possible.
• Let the HVAC system run for a few 15 seconds so that the relearn mode can be activated.
• Start the car.

This process is used on GM cars. Other cars will have their own way of calibrating the HVAC, but the process will be quite similar to the one illustrated.

4) Faulty stepper motor

A stepper motor is a small component found inside the dashboard. A stepper motor is an electromagnetic type of actuator. There are several of them in your car. They measure the RPMs per hour and are mainly responsible for controlling the engine idle speed. Stepper motors are very common in modern cars. The stepper motor failure means a step or a process is being bypassed, and the failed motor makes noise.

Solution

Diagnosing a stepper motor fault requires the expertise of a mechanic to identify the faulty part correctly. Some stepper motors can be repaired, while others will need to be replaced depending on the extent of damage.

To solve this problem, you should start by disconnecting the pigtail connector. After replacing or repairing the stepper motor, you should calibrate the system since the control module has been scrambled and needs to relearn.

What else causes a clicking noise when the car is off?

There are other reasons your car could be making a clicking noise when the engine is off. Knowing these causes will help you rule them out in diagnosing actuator clicking noise. The following are the leading causes;

1. Faulty body control module (BCM) - the BCM is the computer responsible for a number of systems relating to the body of the vehicle. A faulty BCM can cause a clicking noise when the car is off. When the engine is started, you may also find warning lights relating to the BCM also appearing on the dash.
2. Weak battery - this noise will be heard when you are attempting to start the engine. A weak battery does not have sufficient current to power the ignition system hence the engine. When you have a weak battery, turning on the ignition key or pressing the start/stop button will be accompanied by a continuous clicking noise. The noise will also be accompanied by flickering dashboard lights. The solution to this problem is to recharge the battery or replace it if it is dead.
3. Wiring problem - A poor connection in the dashboard may cause the car to make a clicking noise when the car is off. The dashboard could be faulty, or the reassembly of the dash components may have been done wrong hence the clicking noise problems. the answer to this problem is to have a professional mechanic work on the car rather than try to guess what could be the problem.

Conclusion

Reading this article has allowed me to appreciate the importance of checking and resolving the actuator clicking noise, which some drivers ignore. Before attempting to resolve a clicking noise in your car, you must first establish the problem. With modern technology, you have an OBD-II scanner, which can help you know exactly where the problem is.

Resolving an actuator clicking noise will best be resolved when proper diagnostics have been done. The OBD will help you identify the problem, but a professional mechanic will easily tell you why the blend door actuator is failing. Professional mechanics check the entire system to make sure the clicking noise has been resolved once and for all.