2003 540 amplifier vs. radio

[sealbeach740]

Hello,

Does anyone know for a 2003 540 with Nav & DSP does the radio control (turn on) the amp, or does the amp control (turns on) the radio?
I'm trying to track down a slow battery drain and I'm wondering if I unplug the radio if that will then not allow the amp to turn on, or if I unplug the the amp, will that not allow the radio to turn on?

Thanks!

[JimLev]

In a non-DSP system the radio turns on the amp. The DSP system should be the same.
Unplug to amp and see if your drain stops.
How about the FSU?

[sealbeach740]

Thanks Jim.
The FSU was replaced around 5K miles ago for wacky fan operation (that is fine now).
So, if I put fuse 58 (10amp) back in, and disconnect the just amp (& the amp is the problem, and I realize mine won't be the first amp that has issues), I should see the same results as i when I had fuse 58 pulled out. If that's true, the problem should be the amp (vs. the radio being the culprit), right?
Thanks for the info.