Thor Forums

[FW28z]

Typically stereos have two 12V inputs. One which is on all the time (which in the case of the Jensen would be B7) and the other connected to the ignition switch (B4 for the Jensen).

The way it typically works is that the stereo is (allowed to be) turned on and off with B7 having 12V on it from the ignition/acc switch, while B4 is on all the time as a keep-alive voltage for the clock and memory.

That way, the stereo turns off (with the keep alive voltage remaining on) whenever you turn off the ignition switch.

Often in boats, what happens is that the two 12V lines are tied together so that you have to turn the stereo off with the on/off knob or the stereo will remain on - draining the battery. This is done because many people like to listen to the stereo on a boat without the engine running (as most boat ignition switches do not have an acc position).

How Thor does it? Who knows.