A3 Headunit packed up

s3tle

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Hello i have a 1999 A3 1.8t which has a aftermarket Kenwood PS9521(i think) headunit fitted. It has all the audi wiring intacted and is plugged in via the iso blocks.

Its has been fitted for about 2 years and until today worked fine, but has now stopped working.

I checked the fuse on both the headunit and in the fuse box by the door and neither have blown. I next removed a working sony headunit from another car and plugged that in and it also would not work in the audi.

So the problem is with the car not the headunits, but i not sure what else it could be, all the wires going into the iso blocks on the car are in place and not lose. I've checked the three fuses by the battery and they are all fine too, are there anymore hidden away?

Thanks for reading this and any ideas!!
chris
 
Get a 12v testing screwdriver and actually check there's no 12v supply at the HU, both permanent live and ignition on live. These are 2 different 12v supplies and either one failing will prevent the HU from turning on.
You need to check both fuses at the fusebox, not just one. Theres one for Radio (perm live), and another for Radio S-Kont (ignition on live).
 
hi AndyMac
thankyou for answering, i don't have a testing screwdriver so i'll get one tomorrow and check out if there is any power. Had a look at the fuses and i don't seem to have a S-Kont?? any ideas?
thanks
 
You should do on a 1999 model unless it's a very late '99. Should be fuse 30 IIRC, and ensure you are using the map inside the fusebox lid as the manual is not always accurate.
When you pull the HU out you'll be able to see if it uses a second power feed to turn on with the ignition or whether it uses the CANBUS.
You'll need the HU removal keys to get the HU out, and be very gentle with them as they can easily knacker the metal clips. Insert them with the angled sides facing inwards, push the HU in slightly to help release it. Feel for some resistance on the keys as they disengage the spring clips. I'd recommend removing the glovebox so you push from behind once the clips are disengaged. DO NOT pull on the keys themselves as if they haven't engaged properly you can scrunch the clip and then you'll need to prise off the whole front fascia of the HU. You have been warned.
 
hello,
thanks andymac, my fuse number 30 is for the 'Sliding Roof' roof so i guess it is a very late '99. Not exactly sure what the Canbus would look like so i to a picture, i have four connectors a black, red and brown all the standard iso size, and a smaller yellow connector, i guess this is the Canbus?

DSC00040.jpg



Also got a multimeter today tested the wires and there is a 12v feed from the red and white wire in the black connector, the feed seems to vary a bit between 6 to 12v but is on all the time.

I guess if it is CanBus i'll try wiring it back up with that in mind and see if it was just a lose wire?,
i'll run a search on the forum for canbus and see what i can find
 
Are there only 2 connections on the black power connector? (can't quite see from the photo). You should have a brown wire for ground, permanent live on the red wire above it and then a yellow/red striped wire 2 along from the ground, which is ignition on live. This should light up 12v with the engine running and stay lit up until the keys are pulled out.
ISOPowerdiag.jpg

The yellow mini ISO is the rear pre-out feed to the rear amp & sub. You're also missing a green connector (same size as the yellow one) which provides the link to your DIS and then became the CANBUS connection on later models.
The big red connector is just the brightness control linked to the DIS/instrument brightness. It also has handsfree connections for muting the radio etc which aren't wired unless the car was ordered with the Audi kit.
A3BlaupunktConcertDiag.jpg


I take it you don't have a CD changer as there's no blue mini-ISO. It looks a bit wier to me as I've never seen stock wiring as minimal as that. Normally the yellow pre-out connector is part of a blue/green/yellow connector, or is one big solid black connector. Never seen it on its own before.
AudiMiniISOblock.jpg
 
thankyou! very helpful pictures!

Been back out to the car and there are no green or blue connectors hidden away.
The black connector has three wires, one Brown, one Blue, one red and white which has a permanent live. That it just the 3 wires. Sorry for poor images, cameraphone.

DSC00043.jpg



The car came new from audi with a 'aftermarket' sony minidisc headunit rather than a audi chorus or similar. When the sony and the kenwood were working they both had to be switched off rather than turning off when the keys are removed. Also the dimer on the kenwood would not work when the headlights are turned on.

I also have a converter block which converts the yellow block into phono sockets so that fits with you saying about them being for the sub.

So i guess both headunits were wired to the permanent live, and it must of come lose, i'll find a kenwood wiring diagram and see if i can wire it back up.
 
Yes you just need to locate the ignition on feed on the Kenwood (usually yellow or red) and twin it with the perm live with both connections going to the perm live on the black Audi connector.
If the Kenwood has flying leads then the 2 lives will have inline fuses on them.
If it just has an ISO plug on the back then you'll need to link the perm live to the ignition on live on the Audi plug, or buy a power ISO adapter and do it on that.
 
thankyou AndyMac for your help got the headunit working again! must of been a lose connection somewhere!
One last thing can i connect the brightness control wire in the red block to the dimmer wire on my kenwood headunit?