My 2007 Mitsubishi Galant's high beams will periodically turn on randomly when driving or the vehicle is parked. Occasionally coming on in the middle of the night
The car is full of digital electronics and switching duties carried out in many cases by black boxes via unconventional circuits; often an oscilloscope is more use than a voltmeter in fault finding and a deep understanding of the systems involved.
A deal of detective work is likely to be needed - observation. When the lights come on do they come on cleanly or is there some flickering? When they come on must they be switched off or do they go off without interference? Do the lights normally illuminate when the central locking/alarm/immobiliser is armed?
Studying the wiring diagram should reveal the pathways by which a fault could send current to the headlamps. Often, for instance, the headlamps can only be operated when the ignition is switched on but such things as the horn, hazard lights, interior lights, parking lights and headlamp flashers are typically on a battery circuit. If this is so it increases the chance of the problem being with the wiring of the multiway switch (indicator, flasher, dipswitch)...
Thanks for the response! They usually stay on but will sometimes randomly turn off on their own. They do come on cleanly. I just removed the fuses to the high beams and my regular lights are now coming on randomly. The lights must be manually engaged to turn on normally.Thanks for the response! They usually stay on but will sometimes randomly turn off on their own. They do come on cleanly. I just removed the fuses to the high beams and my regular lights are now coming on randomly. The lights must be manually engaged to turn on normally.
I can only repeat the need to study the wiring diagram to become familiar with the circuit and continued observation to discover any pattern. Disconnecting or isolating (removing fuse) various circuits might lead to further clues.I can only repeat the need to study the wiring diagram to become familiar with the circuit and continued observation to discover any pattern. Disconnecting or isolating (removing fuse) various circuits might lead to further clues.
Answers & Comments
The car is full of digital electronics and switching duties carried out in many cases by black boxes via unconventional circuits; often an oscilloscope is more use than a voltmeter in fault finding and a deep understanding of the systems involved.
A deal of detective work is likely to be needed - observation. When the lights come on do they come on cleanly or is there some flickering?
When they come on must they be switched off or do they go off without interference?
Do the lights normally illuminate when the central locking/alarm/immobiliser is armed?
Studying the wiring diagram should reveal the pathways by which a fault could send current to the headlamps. Often, for instance, the headlamps can only be operated when the ignition is switched on but such things as the horn, hazard lights, interior lights, parking lights and headlamp flashers are typically on a battery circuit. If this is so it increases the chance of the problem being with the wiring of the multiway switch (indicator, flasher, dipswitch)...
Thanks for the response! They usually stay on but will sometimes randomly turn off on their own. They do come on cleanly. I just removed the fuses to the high beams and my regular lights are now coming on randomly. The lights must be manually engaged to turn on normally.
I can only repeat the need to study the wiring diagram to become familiar with the circuit and continued observation to discover any pattern. Disconnecting or isolating (removing fuse) various circuits might lead to further clues.