Can a BCM switch turn off the headlights?
If so, the BCM can turn off the headlights to save battery power. In more complicated and more recent designs, car makers run a single wire to the multi function switch to control headlights, high beams, parking lamps, turn signals and hazards. How can they accomplish all that with a single wire? Simple, the switch contains several resistors.
Where does power go in a BCM Body Control Module?
The power then flowed to the headlight switch, and from the headlight switch to each headlight. The wire used for the run from the fuse to the switch and from the switch to the headlights had to be a large enough gauge to handle the current load of the headlights.
How is a headlight switch connected to a relay?
The headlight relay is switched by the BCM, which in turn is commanded by the headlight switch. In this case, the headlight switch acts as an input to the BCM. In most cases the wiring to the headlight switch is just a single small gauge wire.
What happens if you leave your headlights on?
The wire used for the run from the fuse to the switch and from the switch to the headlights had to be a large enough gauge to handle the current load of the headlights. If the driver left the vehicle with the headlights still on, the current draw would drain the battery.
If so, the BCM can turn off the headlights to save battery power. In more complicated and more recent designs, car makers run a single wire to the multi function switch to control headlights, high beams, parking lamps, turn signals and hazards. How can they accomplish all that with a single wire? Simple, the switch contains several resistors.
What happens if a car security light is blinking?
If the security light is blinking the immobilizer system is enabled and will not allow the car to start. What Goes Wrong? Most cars today have a security system built into the electrical system (BCM – Body control module) to deter from theft. The problem is it can sometimes stop the person that owns the car from starting the engine as well.
What can a bad BCM Body Control Module do?
Keep in mind that the body control module is simply a computer with programming, inputs and outputs. A bad BCM body control module can prevent you from scanning for trouble codes, kill your digital instrument cluster and gas gauge, and prevent you from turning on lights or starting the engine.
What should I do if my PassLock security light goes off?
If nothing happens or the engine starts and dies, the security light will be flashing. Wait ten minutes. The flashing light should go off or illuminate without flashing. When it does, turn the ignition off, wait twenty seconds, and then try to start the engine. If it starts and runs, everything is okay.