Quick electronics question

[m_c]

I've spent far too much time this evening thinking about this, and my head is now scrambled for something that should be pretty trivial!

In the attached diagram, will the LED/resistor cause any current to flow in the line marked as 12-24v (that's the voltage to be switched to gnd, not an actual 12-24V source)


I'm pretty sure it won't, due to the LED blocking any flow from the 12-24V, so it won't cause the 12-24V to be reduced as no current will be able to flow, but I've thought about this that much now, I'm doubting myself...