No power to radio.

[Paullajy]

Hi,
I have an 1997 A4 1.8t sport. The radio was stolen some time ago and I have just got around to renewing it. I plugged it in as normal but there is no power to it. I am relying on all you experts out there to help me out.
Many thanks.
Paul

 

[Siena]

Have you checked the fuse in the main fuse board?

Is the radio a factory, or after market unit?

Some after market units have a seperate fuse on the back, near the plug-in harness, check and make sure it's not blown, if fitted.

Are you checking it's not powering up, or checking that the connector actually has no power getting to it?

 

[Paullajy]

Hi,
thanks very much for the reply, I will check the fuses tommorow.
Somebody today told me that if the radio has been out for a long period of time it cuts off the power. Have anybody heard of this?
Regards.

 

[aragorn]

Nope, only way it could cut the power would be if it shorted out on something and blew the fuse.

The other thing it might be, is that the B5 only provides a single, permenant live as standard, whereas most headunits expect both a permenant live and a switched ignition live. You'll have to either provide the permenant live to both inputs on the head unit (most hu's have a little lead that sits between the hu and the ISO block with some bullet connectors to allow this hookup) or if you want it to work on the ignition you'll have to create an ignition live using a relay and a switched feed from the ignition barrel or central electrics panel.

 

[electricracer]

there is an ignition feed on a b5, definately. it comes straight from the ignition switch and is not fused.

it does sound like a blown battery fuse

 

[aragorn]

well mine didnt have it, and theres a number of threads floating around on here of people who've had to add one to the ISO plug when fitting an aftermarket HU.

I used a relay triggered from the 75x pin in central electrics and patched it into the existing stereo live to create the switched feed.

The stock concert/symphony head unit uses canbus to turn on and off with the ignition, and therefore doesnt have a switched live in its harness

 

[AndyMac]

Not on the B5, it does have a seperate ignition on feed. The only issue is they are wired back to front so you have to swap them over. Only B6 onwards and any 2000+ Audi (maybe a very late B5) have the canbus controlled HU.

 

[aragorn]

Well there was no ignition wire on mine, the ISO plug had only one of the wires populated, the other connector was empty...

It was fitted with an aftermarket head unit when we baught it, and it was basically on all the time. When i was fitting the pioneer i presumed it would be because of the pins being backwards like you mention, however after spending a good few minutes with a multimeter i confirmed there simply was no ignition live, hence adding the relay etc.