Turn signals are a basic but critical safety feature that must be in perfect working order for every vehicle on the road. Whether during routine maintenance or in response to a reported issue, service centers follow specific procedures to ensure turn signals operate correctly. These tests help diagnose problems early and confirm the system is safe and compliant. This article explains the typical testing methods professional shops use to check turn signal function and what vehicle owners can expect during a service visit.
Visual and Functional Checks
The first step in testing turn signals is a simple visual and functional inspection. Technicians activate the turn signals one side at a time and walk around the vehicle to ensure all bulbs flash at the correct rate, brightness, and duration. This check includes the front and rear turn indicators, side mirrors (if equipped), and dashboard indicator lights. Look for the Auto Repair in Columbus, NE based service in this case.
If a signal doesn’t light up or flashes unusually fast (hyper-flashing), that can indicate a burned-out bulb or a change in electrical resistance—especially common in vehicles that have had recent LED conversions without the proper resistors.
Switch and Stalk Operation
Next, technicians evaluate the turn signal switch or stalk on the steering column. They check for a firm, positive feel when engaging the signal and verify that it cancels automatically after a turn. If the switch feels loose or fails to stay in position, it may point to a worn-out multi-function switch that requires replacement.
Service centers will also test hazard lights, which use the same bulbs and circuitry. A problem in the hazard system can help pinpoint a shared wiring or flasher issue affecting the turn signals.
Electrical System Testing
If a turn signal issue is suspected to be electrical, technicians use multimeters or scan tools to check for proper voltage and continuity in the wiring. They may perform resistance tests to identify corroded or broken wires. Technicians also examine grounds and connectors, which are common failure points.
In modern vehicles, scan tools can communicate with the body control module or lighting control unit to retrieve fault codes and check signal input/output data. This helps diagnose ECU-related problems or sensor errors affecting the turn signals.
Bulb, Socket, and Relay Inspection
Shops often remove bulbs to inspect them for damage or discoloration. Sockets are checked for corrosion, looseness, or overheating—common issues that can lead to flickering or non-functioning signals. The turn signal relay or flasher module is also tested, especially if signals don’t flash at all or click erratically.
If needed, replacements are made with OEM-quality parts to ensure compatibility and long-term reliability.
Conclusion
By following a thorough, step-by-step testing process, service centers ensure turn signals are functioning safely and efficiently. These procedures help identify and resolve issues before they become safety hazards. Regular inspections during routine service keep your vehicle roadworthy and your signals dependable every time you drive.