remote central locking not working!

[am8631]

im in the process of changing the headunit and now i cant open the car with the keyfob. Car starts ok and the central locking still works with the key, i just cant do it remotely.

At the same time i do not get an alarm if i leave my lights on. I have read on here that this might be a common prob with the car still thinking the key is still in 'ignition', but i dont know how to fix it?!!

I have changed the batteries in the keyfob and have tried reprogramming the key by unlocking the door and holding unlock for 10 secs but still no luck.

I only have the one key, so any help much appreciated guys.

[shineydave]

is the interior light still working when you open the door, if it's not then you've popped a fuse, i'll bet the door open warning isn't appearing in the DIS either.

look on the fuse box lid, it'll tell you which fuse it is

[am8631]

just been out to check the interior light and it comes on as normal when i open the door

[shineydave]

just tried mine and you may be right, can't use the remote when the key is in the ignition. are you getting a fairly pronounced click when you take the key out?

[am8631]

not really, seems to go in and out very easily. I have squirted a bit of WD40 in the ignition but doesnt seem to have done anything?

[davidhodgkinson]

As you pull the keys out of the ignition your interior light should come on (well they do in my S3). If yours does this, it might not be the ignition.

Sorry I can;t be anymore help....

[am8631]

ok, im thinking it might be the s contact switch sticking and making the car think its still in 'ignition mode'. This is because the radio stays on and the lights on warning doesnt sound when the key is removed.

Does anyone know how to test or fix this?

ta

[shineydave]

just had a thought, not sure but i think the accessory supply from the ignition switch goes to a different position on the head unit loom on Audi radios than it does on an aftermarket radio. wonder if you're getting a back feed up that wire that is feeding whatever the "S" contact feeds to tell the car the ignition key is out

errr........if that makes sense

[am8631]

sounds good to me!?!?

any idea which wire that maybe - colour?

ta

[shineydave]

no idea but i do know the switched live has to be re-routed, i'd guess at the moment it's connected to a permanent live which would probably be red, usually you either buy an adapter loom or you move the wire

[am8631]

sorry for all the questions but we might be getting somewhere as the radio is definately on a permanent live at the mo.

I do have a loom adaptor but i still had to butcher a couple of speaker wires. So, are you saying i need to swap the perm live with a swithed one or do i do something else? Sorry for being dumb!

[TDiAvant]

Well I'm not sure what car you have, but on the B6/B7 A4, you have to do the following to enable the remote keys to work again.

Put the key in the ignition and start the engine
Switch engine off after about 2-3 seconds
Close the drivers door and press the lock button on the key fob
Do this for all keys

[shineydave]

i'm not too sure, you really need to check what goes where on the back of the original Audi radio (there'll be connection diagrams on there) then make sure the switched live and permanent live that go to the new unit are actually in the right place

[am8631]

Sorted it!!!!! There was a white wire that was not connected with my wiring harness, i connected that to a swithed live and all working again!

Thanks for the input shineydave, much appreciated.

[shineydave]

not quite the solution i thought of but i figured it had to have something to do with the headunit since that was the last thing you touched. glad it's sorted