I just installed a Headunit in my truck and was wondering which wire on the stock Radio harness was the automatic sound wire (the one that makes the volume go up and down)? Thanks in advance.

 

there isnt a wire thats specifically called that... what problem are you having?

this is usually what a harness looks like minus the remote turn on wire:

 

I was thinking about this last night and it really got the best of me. You're talking about the SVC (Speed Volume Control). Seems like it wouldn't be wire, but rather a feature of the stock HU, but it would still need the information from the speedo to sense how fast you're going. What I'm trying to get at is I think you'd be looking at more than simply a single wire. Could be 100% wrong as well...

 

yea i dont think you will be able to use that feature with the new headunit

 

Well there is that feature on my headunit. I will try playing with the feature in the radio, maybe it gets its signal from something that is already connected. I was thinking that it might be something in the lower Cassette tape wires or the optional CD changer plugs.

I am really hoping that Hillbilly will post on this issue. Thanks for the help already guys.

 

Ok, if I'm understanding this correctly, your after market hu has the feature that alters the volume of the music as your speed changes, correct? If so, you will need to connect to the speed sense wire. I'm not sure where it is, but I should be able to find out for you tomorrow when I go to work since I have access to better sites there. It's probably at the BCM, but what color wire...I dunno. It's fairly difficult to test for as well.

 

Yes I have the feature that turns the volume up and down on both the stock HU and the aftermarket Blaupunkt HU, there is a seperate wire but I was not able to find anything to connect it too.

I haven't figured it out yet, it hasn't been a big deal as I can adjust the sound as needed easily, and with the iPod I have it set to make all tracks the same volume so it doesnt flucuate. But if you could find that, that would be awesome. Thanks.

 

Your speed sense wire is a purple wire, will have to set meter to AC voltage. It is at the ECU (far right behind the glovebox, pin 14 of a 26 pin plug


but you need a meter that will test frequency to be sure