Good to know what you are doing, seen Best Buy installations where they tapped into what they thought was a 12 V source that was part of the IP circuitry.
While BCM's and PCM's are grounded to the vehicle, use a single point ground, if you tap into one of these wires for a ground, would form what is called ground loops that will mess these systems up. Another issue is the CMOS logic is used, very high impedance and highly subjected to EMI. If you run a high current speaker wire just a tad too close, can mess these systems up. Can even do this by running a negative ground lead to the negative post of the battery for a high current power amplifier that will be close to any of the engine control wires.
You really have to know your vehicles electronic system. Alternator output is sure not a pure DC current, but a series of pulses that can also produce interfering EMI. As are ABS pulses, can mess up your brakes.
While BCM's and PCM's are grounded to the vehicle, use a single point ground, if you tap into one of these wires for a ground, would form what is called ground loops that will mess these systems up. Another issue is the CMOS logic is used, very high impedance and highly subjected to EMI. If you run a high current speaker wire just a tad too close, can mess these systems up. Can even do this by running a negative ground lead to the negative post of the battery for a high current power amplifier that will be close to any of the engine control wires.
You really have to know your vehicles electronic system. Alternator output is sure not a pure DC current, but a series of pulses that can also produce interfering EMI. As are ABS pulses, can mess up your brakes.
