Owner's Problem Description
The owner of a 2010 Acura TL reports intermittent electrical issues occurring after a remote start installation by Best Buy. Symptoms include non-functioning driver headlight and fog light, a turn signal that remains on without activation, and a malfunctioning heater. These issues have happened about six times in three days. The owner is considering having the dealer inspect the vehicle for potential computer shorts.
Professional Technical Analysis
The 2010 Acura TL with a smart key and tech package is experiencing multiple electrical anomalies post remote start installation. The vehicle exhibits symptoms such as non-illuminating driver side headlight and fog light, persistent activation of the driver's turn signal, and inoperative heater, happening intermittently over the past three days. Given the timing of these faults following a non-OEM installation, it is prudent to investigate potential wiring or grounding issues that may have resulted from the remote start installation. It is common for aftermarket installations to inadvertently disrupt existing electrical systems, particularly in vehicles with complex body control modules. The vehicle's estimated mileage and previous repair history should be reviewed to rule out other potential causes. Given the integrated nature of the vehicle's systems, it is critical to assess how the remote start system interfaces with the vehicle's CAN bus and body control module (BCM). Possible fault codes that may arise include B1000 (BCM malfunction) or B1320 (headlight circuit fault). The current condition raises safety concerns, as malfunctioning lighting can lead to visibility issues while driving. Additionally, the inoperative heater may indicate a more systemic electrical failure affecting the HVAC system. A thorough diagnostic using a professional OBD-II scanner or GeekOBD APP is recommended to capture any stored fault codes and live data indicating the state of the affected systems.
Possible Causes
Most common causes (ordered by frequency):
- Ground Connection Issue: The remote start installation may have disrupted the factory ground connections, causing intermittent electrical faults. Inspection of ground connections, particularly at the battery and under the dash, is crucial. A loose or corroded ground can result in erratic behavior of multiple electrical components. The resistance across ground connections should ideally be below 5 ohms. If the resistance is higher, clean and resecure connections. This issue is common in installations where multiple components are added to the vehicle's electrical system. - Intermittent electrical issues, troubleshooting by shaking wires showing sensitivity to connection quality, visible corrosion at ground points.
- Faulty Body Control Module (BCM): The remote start may have inadvertently affected the BCM, which manages various electrical systems, including lighting and HVAC. A BCM failure can lead to persistent faults like the turn signal malfunction. Symptoms may also include sporadic operation of lights and climate control. Diagnostic codes related to BCM faults should be retrieved, potentially indicating communication errors or internal failures. Typically, a BCM replacement would cost between $300-$600 including labor. - Persistent electrical malfunctions, possible BCM-related DTCs, erratic lighting behavior.
- Remote Start Wiring Error: Incorrect wiring during installation could cause short circuits or open circuits in critical systems. It's essential to check the installation harness for proper connections, ensuring that all wires are secured and insulated. Faulty wiring can lead to various symptoms, including malfunctioning lights and HVAC controls. A thorough inspection should involve checking the continuity of wires and verifying proper voltage levels at the connections. This might require tracing back to the installation points. - Installation performed by Best Buy, potential signs of improper wiring, intermittent failures directly correlated with remote start activation.
Diagnostic Steps
Professional Diagnosis Process
Follow these systematic steps to accurately diagnose the issue. Each step builds on the previous one to ensure accurate diagnosis.
- STEP 1 - Initial OBD-II Scan: Begin with a comprehensive scan of the vehicle's systems using a professional OBD-II scanner or GeekOBD APP. Ensure to capture any stored fault codes and examine freeze frame data, especially around the time of the reported symptoms. Look for BCM-related codes, as these may provide insight into the underlying issue. This step is crucial in identifying any immediate faults that may need urgent attention.
- STEP 2 - Visual Inspection: Conduct a thorough visual inspection of the wiring harness associated with the remote start installation. Check for any signs of frayed wires, loose connections, or corrosion, particularly at grounding points. Ensure that all connections are secure and that there are no exposed wires that could cause shorts. This step helps in identifying any obvious installation errors that may lead to the reported symptoms.
- STEP 3 - Ground Testing: Test the ground connections to ensure low resistance (ideally under 5 ohms). Use a multimeter to measure resistance across ground connections. If the resistance is higher than expected, clean and re-establish the ground connection to ensure proper operation of electrical systems. This step is essential in confirming that grounding issues are not contributing to the electrical faults.
- STEP 4 - Component Functionality Check: Check the functionality of affected components, including the headlights, fog lights, and HVAC system. Utilize the GeekOBD APP to monitor live data while activating these components to confirm their operational status. This step will help to isolate any components that may be malfunctioning and require further diagnosis or replacement.
