As I understand it, most electrical circuits in cars have:
- a primary side (control) and secondary side (active?), with a relay being the nexus between each side.
- signal wires going to the relay are either from a user-controlled switch (e.g. power window switch) or a sensor (e.g. coolant temp sensor)
Bi-directional scanners can control electrical components, so they must be wired up to the secondary side in some way. However, I haven't been able to find information on how they do this. Does anyone here know how they are wired into electrical circuits to be able to control components?