Skip the auto shop - Our mechanics make house calls

Q: Dome light and trunk light not working all fuses are good

asked by on

ive checked fuses and the dome lights and trunk light are still not coming on theres no power to the dome light i check with tester is there any switches or anything that could be turned off

My car has 160000 miles.
My car has an automatic transmission.

A: Your lights have a BCM (Body Control Module...

Your lights have a BCM (Body Control Module) that can control them. It is setup this way to save your battery if your interior lights are left on. The dome light is grounded by the BCM and your trunk light is powered by a relay that the BCM can turn on or off. There is a lot of electronics involved with this system and a scanner would be very helpful. There is one thing you can try that may or may not be helpful. With the key on, open and close your doors one at a time and see if the door ajar light comes on on your dash. All of the door switches go through the BCM. Then the BCM sends this information to the instrument cluster via a CAN (Computer Area Network). This is simply one test that might reveal some answers for you.

Unfortunately due to the nature of dealing with computer modules, it is hard to give detailed advice here. If you have access to a professional level scanner, you will be able to use the scanner to see what information is being relayed from module to module. There is quite a learning curve to such a venture though. I recommend you have this electrical issue diagnosed by a certified technician, like one from YourMechanic.

Good luck and be patient with this one!

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!

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: Lights on dash suddenly started flashing while driving, accompanied by car surging & stalling

The vehicle may have a problem with the power relay in the central junction box that powers the ignition and computer on the car. The relays and connections to the junction box will need to be checked if the problem...

Q: car wont start.

Hello, thank you for writing in. Low or no compression in the cylinders can be cause by several issues. If the starter is turning too slowly, the air is able to escape through the gaps in the piston rings, and...

Q: Power seat will move forward but not back, how can I fix this?

Hi there. It sounds like the adjuster motor is failing, seat track is binding, or the switch has failed. Check for power and ground to the motor while using the switch; if they are available upon command, then the motor...

Related articles

How Long Does a Heater Control Valve Last?
Keeping the right amount of coolant in a car is essential in keeping the engine at the right temperature. Failing to have the right amount of coolant or even bad elements...
P0052 OBD-II Trouble Code: HO2S Heater Control Circuit High (Bank 2 Sensor 1)
P0052 code definition HO2S Heater Control Circuit High (Bank 2 Sensor 1) What the P0052 code means This code is seen when the Engine Control Module (ECM) tries to control the...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...