so i have read the 100+ threads about this and im still confused..... I have a 88 vert with working headrest speakers... i want to install an aftermarket radio because the stock sounds horrible, but i want to keep the headrest speakers, and controls.... from what i have read, the amp for those speakers just needs the signal wire to turn it on...? this is where i am confused, the OEM radio turns the speakers on they work fine... I put the aftermarket radio in, they dont work... i dobule checked my wiring still nothing... i assume the the blue/yellow wire from the car would be the lead for the amp, sense it has the amp 12v lead from the head unit going to it, but still nothing.... it is getting power.... any help is appreciated, i just want them to work and its driving me nuts.

 

You first need to activate the amp with a remote signal such as the one you would typically wire to an amplifier. (Must always be active as long as the stereo is on!!) The s4 and s5 stereo system do not have a difference. Re read the diy and make sure your doing everything as stated in it. Check what you are wiring the speaker outputs to and make sure that they are going towards the headrest speakers and not the doors. Btw, the location of the headrest amp is in that convertible cover on the drivers side

 

alright may be I was wrong... I'll take a look at it again... I really don't want to lose the speakers or controls.

 

Did you ever figure it out. I just purchased an '88 vert for my daughter and it has an aftermaket radio and the headrest speakers don't come on. LMK if you ever got it going and what you had to do. I'll be checking if the old owner wired everything ok tomorrow.
Thanks, Anthony