i have a sony in dash video player model DVX-11A and a clarion equilizer (volume control) model EQS755 in my vehicle. here are the installation manuals for both units
sony: https://www.sony.com/electronics/sup.../W0004125M.pdf
clarion: https://www.clarion.com/us/en/pdf/EQS755.pdf (page 10)

I had a shop install this for me, but since the equilizer has no power button, when i press the power button (off, number 8 on page 8) to turn off the player, the equilizer stays on. power only goes off when i turn the ignition to off.

i do not want to add a switch somewhere in the vehicle. i just want to disengage power to the equilizer when i press the power button on the player. per the wire diagrams in the manuals listed above, what would i need to change to engage this; so that pressing the power button also cuts power to the equilizer?

 

The EQ looks to have a "remote on/off", the blue wire on page 10, I ASSUME this connection gets 12v to trigger ON, and 0v for OFF but you would need to check that, is there a JUMPER wire in that slot now?

I don't see that type of connection on the Sony, it doesn't seem to be made to control external equipment

You could use a line level audio sensor on one of the RCA connections, doesn't effect signal
And then a relay that sends 12v to "Blue wire" connection, when audio is present, no 12v when no audio, you would want a timer circuit to hold relay closed or it would cut 12v between songs

ST-ACR1 does this but expensive, $100 + 12v>24v power supply
Only a max 5sec delay, might be enough though

 

i checked the connections at the back, and the blue wire on the equilizer has a wire (jumper?) with a crimp splice, connecting the blue wire; to the red wire of the player. what is this jumper currently doing?

in spite of the liklihood that the sony cant control external equipment, is there some sort of wire job i could do, other than spending any money on sensors, relays, et cetera, that will kill power to the equilizer when i press the off button on the player??. if i need to, id be fine opening the sony to attach a wire somehow to cut power to the clarion when i press the off button on the sony

 

The blue wire tells the EQ to stay on all the time, well while the Sonys red wire is 12v, key on, you could put a separate switch on that wire

No, I doubt there is a 12v circuit in inside the Sony, maybe a 5v power supply, but then you would need a 5volt relay

Maybe contact Sony to see if you can get a circuit diagram of the unit

 

alright ron. is there any way i can modify the connection of this blue wire (without additional switches) so that i can control when it has power? what would i look for in that circiut diagram from sony? then, what if there is a 12 volt circuit in the sony?

 

Any 12v on/off should activate it, I can't see blue wire being an amp "draw", it should just be a trigger for a transistor

i.e. the blue wire doesn't power the EQ, its just an on/off switch

 

so what if sony tells me the player does have a 12 volt circuit and they identify its location? what do i do then?

 

Run a wire from "it" to the blue wire connection/port on EQ, disconnecting current blue wire connection

When that port has 12v EQ turns on, when 0v it turns off, from what you have already said and from diagram, its the remote on/off "switch"

 

so then, when i do that, and then press the off button on the player, the equilizer will also go off?

then, what happens when i press the play button on the player? play, in essence is the power on button for the player. when i do this modification youre talking about, would play also give power to the equilizer again? --the off button is for off only, it does not apply power also.

 

The EQ has separate 12v and ground power wires, so always has power, I assume, as long as key is on

The blue wire port is a remote on/off to be used with "radios" that have a "remote" trigger on the back, to turn on and off an EQ or amplifer
It doesn't "power" the unit, its just a trigger voltage, no amps, to "tell" EQ, or amp, to turn on or off with the "radio"

So you need to find a 12v circuit inside the "radio"(player) that ONLY has 12v when unit is turned on, and then 0v when turned off

 

and i am currently waiting to hear from sony support to go any further in this