Viny, Vijay.....do share your details of your power connection setup. Waiting for that. I double-checked mine. It is yellow to yellow and amp powers on and off exactly with the HU. If i switch off the HU with ignition on, the amp goes off as well. Viny...u may be right that its a constant supply on yellow cable....so along with what i observed the best explanation to me seems to be that amp swithces on itself when it detects audio signal from HU. So yellow cable gives it contant power but this signal detect feature works as a on/off switch. The red cable will allow you to power on the amp when the key is turned as it is ignition mode power. Wanted to try myself plugging the red cable in, but that HU is very difficult to put back in after the PnP mod. If you can...try to plug red one first and see if you can use the amp without the key turned on. My take is that HU will power on but amp will not. Crux being...as HU can power on/off independently as well as with ignition, it gives out the same options for the amp as well through red/yellow cables.