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

asked by on August 24, 2016

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.

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!

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