Bluetooth retrofit power question

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magnus911

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Hey Guys,

I'm hoping for a quick response on this one because although I've lived with it since I retro'd bluetooth, I'm selling the car this weekend and want to fix this issue for the new buyer.

Essentially, I retro'd bluetooth with help from a techie friend of mine and it works great. Now, as far as I can remember, we took power from the RNS-E which is powered without the key in the ignition.

So, when I leave the car for more than two days, the BT unit drains the battery and I have to jump start the car (not good I know so once it had happened twice and I realised what I'd done I started removing the BT unit when I knew I wouldn't be using the car for a day or so).

So, to all you retrofitters out there; when I dismantle everything tomorrow, where should I take a live feed from so that I can be sure the BT unit will only power up when the ignition is turned on?

I hope I've made sense!

thanks in advance...

<M
 
You'll get switched live from the fuse box on the side of the dash.

Take a tap off this fuse. You can either buy a piggy back fuse thing from Halfords or the like or do as I did and wrap the wire around the output end of the fuse.

I think this is the fuse for the rear wiper, but I'll check it out in the morning.

A3SwitchedLive.jpg


I have a Nokia 610 and not the factory BT.
 
If you have already taken a feed from behind the stereo then you are better off taking a feed from the switched live for the RNS-e itself. I'm not saying you're wrong Marc but he would have to re-route wires to go from the fuse box. I don't know what pin it is or what Audi label it as though.

Do you know Marc?
 
I don't believe there is switched live behind the head unit - at least I've never come across one and I've been fitting phone kits to Audis for years. The unit has permanent power and the on\off is controlled either by the power button or by a CANBUS signal when the key is inserted\removed.

I believe that the BT module also requires a permanent supply but that the on\off controls are managed by the CAN High and Low wires via a signal from the head unit.

There are 7 wires in the BT connector which run to the back of the RNS-e

Connector C​
Pin 6 Tel NF in -
Pin 12 Tel NF in +​
Connector D​
Pin 9 Can High
Pin 10 Can Low
Pin 11 Tel Mute
Pin 12 KI 31 GND​
Pin 15 KI 30 +12v

There are two additional wires that run from the BT module to the microphone. No mention of switched live.
 
I see. In that case I would recommend that he fits it as per that, wouldn't you?
 
Thanks for all the responses guys!

So Mark, are you saying that I've just wired it wrongly?

Interestingly enough, when I turn on the ignition, the BT unit will allow me to pair with it, which I understand it will only do for a few minutes after it's been turned on so it must be getting some sort of signal that it's on?

It does definitely draw power all the time though...
 
If the BT unit is working I would assume you have the CAN High & Low wired in correctly as nothing will work otherwise.

This CAN signal is what tells the unit to scan for the pre-defined period.

If the unit is drawing power when it should be off then it could be that the unit is faulty.

The BT unit shouldn't need switched live to function so wiring it in that way would not be recommended - you could give it a go and see if it works, the only thing is that as soon as you turn the key off the kit will die meaning that if you are already on a call it will switch back to the handset as soon as you turn the key off whereas with the proper setup it stays live over the speakers for as long as you are on a call and the rns-e is turned on.
 
MarcQuinlivan said:
The BT unit shouldn't need switched live to function so wiring it in that way would not be recommended - you could give it a go and see if it works, the only thing is that as soon as you turn the key off the kit will die meaning that if you are already on a call it will switch back to the handset as soon as you turn the key off whereas with the proper setup it stays live over the speakers for as long as you are on a call and the rns-e is turned on.
Click to expand...

Marc, you are showing up what a tiny understanding I had of this before, thanks!

At the moment it does behave as it should; other than draining the battery of course!

Is there any scenario, other than a faulty BT box, that might cause the unit to continue drawing power after the key has been removed? Might it be wrongly coded for example?

It'll be a pity if i can't fix it but I'll just have to explain the problem to the buyer.

Thanks for all your input so far, much appreciated!

M
 
I would agree with marc; take a switched live from the fusebox; its quite easy to get the trim panel off on the drivers side. Coding etc will not make a difference to it draining the battery. To check; if the phone stays paired to the BT even when the key is out and you have shut the car; its still on,

Alternatively, take the box out and sell it.
 
H & K revision modules are known for drawing power and killing cars over a short period. What module do you have fitted. Make sure it is a Q module and the problems should go away.

I've had to replace 4 of the K modules so far, AUdi have replaced them under parts warranty. All K modules were with drawn and replaced by Q by AUdi.

If everything is ok, the BT module connected to a perm live is the way it should be.
 
When I fitted mine I took a feed from under the passenger seat. If you have heated, power or lumbar control there will be a switched feed under there, presumably where you situated your Bluetooth interface.
If not then behind the Rns-e or fuse box will be your best bet as already stated
 
The911SC said:
Alternatively, take the box out and sell it.
Click to expand...

Nice! But the chap who's buying the car is picking it up on Sunday...

He probably won't notice for a few weeks but I'd like to give it to him in good nick and all working...

I'll have a play this afternoon and maybe switch to the other feed.

The phone stays paired if I'm on a call but as soon as I switch off I hear the 'dong' and it unpairs (after I remove the key I mean!)

M
 
s8craig said:
H & K revision modules are known for drawing power and killing cars over a short period. What module do you have fitted. Make sure it is a Q module and the problems should go away.

I've had to replace 4 of the K modules so far, Audi have replaced them under parts warranty. All K modules were with drawn and replaced by Q by AUdi.

If everything is ok, the BT module connected to a perm live is the way it should be.
Click to expand...

I fitted a K version as I had an A version before which had no bluetooth, Had a copule of occasions with flat batterys but think that was interior light. Ive not had it 12months so ill get it replaced, thanks Matt
 
magnus911 said:
Nice! But the chap who's buying the car is picking it up on Sunday...

He probably won't notice for a few weeks but I'd like to give it to him in good nick and all working...

I'll have a play this afternoon and maybe switch to the other feed.

The phone stays paired if I'm on a call but as soon as I switch off I hear the 'dong' and it unpairs (after I remove the key I mean!)

M
Click to expand...
Sounds like the CAN is working properly by telling the BT unit to power down\disconnect BT, but is still drawing power.
 
Ok well thanks for all your comments guys; I think I'll just explain to the buyer that it's a small problem which Audi refused to fix because it's no longer under warranty...

It must be the unit...
 
yes, I fitted it to my rs4 actually since i didnt have tech pack ..
I did it myself but I'll let others comment on fitting based on your location?...
A friend of mine had his fitted by a normal phone install guy as there are step by step instructs available on..

www.navplus.us
 
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