Skip the auto shop - Our mechanics make house calls

Q: Headlights automatically turn on by themselves at night when the car is off

asked by on

My 2004 Chevy Trailblazers headlights, turn on automatically at night while parked in the driveway, after about 5 to 10 minutes of the car being off, the headlights automatically come on. They do not turn off until the battery dies! I tried messing with the switch, and when the headlights turn on, it won't even let you turn the lights off with the switch, after about 3 minutes it will let you turn them off. But after you go back inside for a few, they turn right back on. If it matters, I did get aftermarket light bulbs a couple months ago. But the problem didn't start until last month. Thanks for the assistance!

My car has 174000 miles.
My car has an automatic transmission.

Hello, thank you for writing in. The vehicle may be having issues with the headlight circuitry. This may mean that the sensor, photocell, body control module, replacement headlight, or a fuse/relay has failed. Something is allowing power to be sent to the headlights when the vehicle should be off. One of the quickest way to track down the culprit is to use a voltmeter to trace the power supply when the issue is occurring. This part is important! Do not try and diagnose the issue when the issue is not currently present. Wait and catch it in the act, and then perform the voltage tests. These can be done at home with a voltmeter if you are equipped. If not, contact our service department to schedule an appointment.

Was this answer helpful?

Need advice from certified mechanic? Get help now!

Over 1000 mechanics are ready to answer your question.
The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details

Ask a Mechanic
(100% Free)

Have a car question? Get free advice from our top-rated mechanics.

Ask A Mechanic
Over 10,000 questions answered!
  1. Home
  2. Questions
  3. Headlights automatically turn on by themselves at night when the car is off

Get an instant quote for your car

Our certified mechanics come to you ・Backed by 12-month, 12,000-mile guarantee・Fair and transparent pricing

Get a quote

What others are asking

Q: The bolt that holds the plate for the power steering return lines, what size is it? Is it a torx? Is it a twelve point?

The bolt size that you need is 10 mm and the treads of 20 metric with a torque of 71 inch pounds. The best thing to do is take a thread gauge tool and check to see if the treads...

Q: I am looking for a long-lasting and reliable oil pump.

The best parts you can buy for the vehicle are original equipment parts that were designed to be used from the factory. General Motors vehicles mainly used ACDelco and if you cannot find any at the parts stores, you can...

Q: System Gross Leak Evaporative Emission p0455

The code P0455 will not be fixed by having an oil change and tune up. The evaporative leak may just have been caused by a loose or leaking gas cap. The system will need to be tested by leak testing...

Related articles

What Causes Hoses to Leak?
While the largest part of your engine is mechanical, hydraulics plays a significant role. You’ll find fluids at work in a number of different areas. Your car's fluids include: Engine oil Transmission...
How to Avoid Back Pain in a Car
If you have back problems, sitting in a car for an extended period of time can be excruciating. Even without back problems, you could experience discomfort and soreness from...
P2428 OBD-II Trouble Code: Exhaust Gas Temperature Too High Bank 1
P2428 code definition A P2428 trouble code signifies that the PCM has detected a problem in the exhaust gas temperature sensor circuit in bank 1, which subsequently contains the number one...