Daytime running lights are a safety feature found on many late model vehicles. Daytime running lamps are simply lights on the front of the vehicle, usually built into the headlight assembly, that activate whenever the vehicle is in motion. They are a separate light from the actual headlights, and the light provided by them simply gives an additional visual cue to help make the vehicle more visible to pedestrians and other drivers on the road. Usually the daytime running lamps cannot be manually turned on and off and are controlled automatically by the daytime running lamp module. The daytime running lamp module is the computer that controls the daytime running lamps, and any issues with the module can cause the lamps to not function properly. Usually a bad or failing daytime running lamp module will produce a few symptoms that can alert the driver of a potential problem that should be serviced.
1. Daytime running lamps do not come on
One of the most common symptoms of a potential problem with the daytime running lamp module is daytime running lamps that do not come on. Since the module is what controls the lamps and feeds them power, if the lights fail, the daytime running lamps will be left without power and will not function as a result.
2. Daytime running lamps stay on while the car is off
Another symptom of a potential problem with the daytime running lamp module are daytime running lamps that stay on even when the vehicle is turned off. Most daytime running lights are wired to turn off when the vehicle is no longer in motion, or when the key is removed from the ignition. If the lights remain on even after the key has been removed, then that may be a sign that the module has possibly had an internal or wiring short and is supplying power to the lights even when it is not supposed to. This will cause accelerated wear on the bulbs and housings, as well as a parasitic drain on the battery until the issue is addressed.
3. Burning smell
Another symptom of a potential problem with the daytime running lamp module is a burning smell. If the daytime running lamp module has any issues that interfere with the proper regulation of power to the lamps, it may cause the bulbs, wiring, or even the module itself to overheat. This may result in a burning smell coming from the engine bay, and maybe even faint smoke, as the wiring overheats and the insulation burns up. If this problem is not quickly addressed, it can quickly become a safety hazard.
The daytime running lamp module is a component found on many newer vehicles and is necessary to the proper operation of the daytime running lamps. If you suspect that your daytime running lamp module may be having an issue, have the vehicle inspected by a professional technician, such as one from YourMechanic, to determine if your car needs a daytime running lamp module replacement.
This article originally appeared on YourMechanic.com as Symptoms of a Bad or Failing Daytime Running Lamp Module and was authored by Ed Ruelas.