Remote on voltage on headunit?

[Chaoticatom]

Hi Guys,

First post here, great website!

Just a quick question, does anyone know what the voltage should be for the remote on wire from the head unit to the amp? I'm reading 7.8v and 12.5v on the main power cable (engine off).

I have a 54, A3, 3 door, non bose, concert II. The rear speakers and amp have stopped working and Audi said that the amp had blown. I just wanted to check this myself as I don't trust the dealer.

Thanks.

 

[james0808]

The amp went on my A4.Put a better one in there the audi one is crap anyway.

 

[AndyMac]

Should be 12v, but if the amps blown there could be something dragging it down I guess. Disconnect it then test the remote on feed. If it's still 7v, still 12v on the amp and see if it works.

 

[Chaoticatom]

Thanks AndyMac. I tried putting 12v on the remote wire and the amp kicked into life. This proves to me that its the headunit that is at fault. I love Audi's diagnostics!

 

[AndyMac]

There are other remote on feeds from the HU, but they're buried in the wiring looms. I'd stick a small relay in there, one which can trigger off the 7v.