* Faulty Climate Control Module (CCM): This is the most likely suspect. The CCM is the "brain" of the climate control system. A failing CCM can cause erratic behavior, including flashing lights, clicking noises, and malfunctioning controls. Internal components like resistors or transistors might be failing.
* Bad Blower Motor Resistor: While this usually manifests as different blower speeds not working, a severely failing resistor could cause electrical glitches that ripple through the system, resulting in the symptoms you describe.
* Wiring Issues: Damaged or corroded wiring within the climate control system can cause intermittent electrical problems, leading to the flashing lights and clicking. This is especially likely in an older car. Look for frayed wires, poor connections, or corrosion around the CCM and blower motor.
* Short Circuit: A short circuit somewhere in the system could overload the circuit, causing the clicking and erratic behavior. This is a more serious issue that needs prompt attention to prevent a fire hazard.
* Low Battery Voltage (Less Likely): While less likely to be the direct cause, a very weak battery could cause the electrical system to act strangely. Check your battery voltage.
Troubleshooting Steps:
1. Check the fuses: Start by checking the fuses related to the climate control system in the fuse box (consult your owner's manual). A blown fuse could be a simple fix.
2. Battery Voltage: Test the battery voltage with a multimeter. A low voltage could contribute to electrical gremlins.
3. Inspect Wiring: Carefully visually inspect the wiring harness leading to the climate control module and the blower motor resistor. Look for any signs of damage, corrosion, or loose connections.
4. Access the Climate Control Module (CCM): This is often located under the dashboard, and accessing it requires some disassembly. This is where you'll likely find the problem if the above steps don't yield results. It's usually easier to replace the entire module than to repair individual components inside.
5. Blower Motor Resistor Inspection: If you are comfortable with basic car repair, you can locate and check the blower motor resistor for damage or burnt components. This is usually easier to access than the CCM.
Important Considerations:
* Safety First: Working on car electrical systems can be dangerous. Disconnect the negative battery terminal before starting any work to prevent electrical shocks.
* Professional Help: If you're not comfortable working on car electrical systems, it's best to take your car to a qualified mechanic. Diagnosing and repairing electrical issues can be complex, and a professional will have the tools and expertise to pinpoint the problem efficiently and safely.
The CCM is the most likely culprit given the symptoms, but thorough investigation is needed to be sure. Replacing it is often a relatively straightforward repair, provided you can access it.
