In a positive switching, high current ignition system, which ignition switch circuit has +12V in the RUN and START positions but not during ACC?

In a positive switching, high current ignition system, the ignition switch circuit that provides +12V in the RUN and START positions but not during the ACC position is typically the Ignition #1 circuit. This circuit is responsible for powering critical components, such as the ignition coil and fuel pump, when the engine is running or when starting the engine.

During the RUN position, power is supplied to critical electronic systems necessary for engine operation, while in the START position, it allows for increased current flow needed to engage the starter motor. In contrast, the ACC position is meant for accessories that don't require the engine to be running, such as radios or power outlets, so the Ignition #1 circuit does not supply voltage during this mode.

Understanding this distinction is crucial for diagnosing issues related to the ignition system, verifying system configurations, and ensuring that components are receiving the appropriate voltage at the right times for proper functionality. Other circuits have different roles; for example, the Accessory Ignition circuit would provide power in the ACC position but not in RUN. Thus, it’s clear that Ignition #1 is designed specifically to operate in the specified conditions of RUN and START only.