new head unit.. no power

[A3LeighAUM]

first off let me start by saying i hate doing this ind of thing but needs must.. so new head unit supplied with aerial booster thing and harness.. everything plugs in but i have no power. i believe i have to run a permanent live ???
which wire do i run this from and where is the best place?? also where do i put the blue wire from the aerial booster too ??

pictures get a bit confusing but these show the head-unit harness plugged into another harness which plugs in to the 3 blocks.. one plugs into the rca... hope this is the right harness lol.. any help much appreciated as i need music back in my car

 

[A3LeighAUM]

anyone ?????

 

[HansfishS3]

Check fuses Get an voltmeter....check the pins on the supposed 12V radio loom...are they receiving any power in the first place? Even if your aerial amp isn't plugged in head unit should still receive power

 

[A3LeighAUM]

fuses look good but changed them just to be sure... am i right in thinking i should get some power to the head unit without an ignition live ???

 

[craigt1985]

Need to look into this myself, same thing; installed the head unit with the correct ISO harness adpator and no power. Think i read somewhere you have to take an ignition live, but also Audi did something funky with the wiring and you need to switch a few wires around. Could have misread something and it's bull, but shall be following for a definitive answer.

 

[A3LeighAUM]

its mind boggling lol... soo confusing its unreal

 

[Nilz]

Im pretty sure two of the wires need swapping round to get the power, cant remember which ones though so not much help as i did mine a long time ago.

 

[A3LeighAUM]

had to put the red and yellow on to the red... now to wire a ignition live out

 

[Erikn89nl]

Audi fits the permanent live and the switched live in opposite pins, when compared to ISO connections. However, this doesn't result in no power at all, it results in the radio losing all it's settings when you turn the ignition off.

 

[craigt1985]

had to put the red and yellow on to the red... now to wire a ignition live out

Red and yellow on the Audi ISO block to the adaptor red?

 

[Erikn89nl]

Red and yellow are the switched and permanent live. If you put them both on the same pin, one of two situations will occur:
- it's a permanent live, and you have to switch the radio off manually every time
- it's a switched live, and your radio loses its settings every time you turn off the ignition

 

[A3LeighAUM]

Red and yellow on the Audi ISO block to the adaptor red?

on the halfrauds wiring harness

 

[A3LeighAUM]

Red and yellow are the switched and permanent live. If you put them both on the same pin, one of two situations will occur:
- it's a permanent live, and you have to switch the radio off manually every time
- it's a switched live, and your radio loses its settings every time you turn off the ignition

it's a permanent live, i have the HU front off today whilst the car has been stood, i'm hoping that it's enough to not drain the battery over night.
Am i right thinking an ignition live will correct this ???

 

[A3-Lee]

If it's a facelift car you have to run a ignition live wire from the fuse box to the headunit as the standard unit uses CAN to switch it on as far as I can remember.

 

[Erikn89nl]

it's a permanent live, i have the HU front off today whilst the car has been stood, i'm hoping that it's enough to not drain the battery over night. Am i right thinking an ignition live will correct this ???

If it's a facelift car you have to run a ignition live wire from the fuse box to the headunit as the standard unit uses CAN to switch it on as far as I can remember.

Running an ignition live to the correct pin number in the Halfrauds harness will correct it. See the ISO wiring diagram below:

Not sure how it will be on the facelift models, but on my pre-facelift A3, Audi had switched pins A4 and A7 on the diagram above, resulting in the effects I mentioned above:

Audi fits the permanent live and the switched live in opposite pins, when compared to ISO connections. However, this doesn't result in no power at all, it results in the radio losing all it's settings when you turn the ignition off.

 

[rsvrider]

On the face lift I have I used a connect2 canbus lead no need for any other lead Works the same as oem. I took my Halford one back.

 

[A3LeighAUM]

Running an ignition live to the correct pin number in the Halfrauds harness will correct it. See the ISO wiring diagram below:
View attachment 56291
Not sure how it will be on the facelift models, but on my pre-facelift A3, Audi had switched pins A4 and A7 on the diagram above, resulting in the effects I mentioned above:

that's awesome thank you very much .. not had chance to do anything else with it as of yet but will run an ignition live from fusebox to the correct pin.

next problem is the rear half been way to quiet. think i am just going to replace with a better products..