Where the hell is switched 12v ??? Help pls !

[QuattroRocket]

So I have been spending the last couple hours installing my Lidatek LE30 laser diffuser and other than the damned cars fancy electrical system all was going just fine. I have tapped into fuse #12 in the brown harness which is the wiper and light sensor but the damned thing doesnt turn off. A a matter of fact the entire fuse panel seems live all the time ??? I have closed everything, locked the car and walked 40 or so feet away and the thing stays live all the time

Someone please save my from insanity and tell me where to grab 12v switched power off the fuse panel or let me in on the secret why the entire fuse block seems live all the time

Thanks

[ob_1jr]

the 2013 doesnt have a cigarette lighter does it?

[phillips2024]

get a Mini Add-A-Line and tap into empty fuse position #2.

[Maltitol]

the 2013 doesnt have a cigarette lighter does it?

Yes, it does. Its above just above the shifter.

[QuattroRocket]

Well I am calling it a day until I figure out what's going on here. I don't have a mini add a line so tapping another source is the only choice and it should work fine, for some reason the power stays live 15-20 minutes after the car is closed and armed ?


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[dizzlesizzle]

The only fuses i know that are all switched 12v are the entire "red" row in the trunk fuse box on the right of the trunk. That's what I used for remote turn on for my amp...probably not the best run in your situation but would work.

[QuattroRocket]

Well at least I now have confirmation that the car does indeed have switched 12v ! I had wondered if it was running on a switch to ground setup or something. I must be missing something ???

[dizzlesizzle]

Well at least I now have confirmation that the car does indeed have switched 12v ! I had wondered if it was running on a switch to ground setup or something. I must be missing something ???

I just read your signature and you have a 2013...the red row in the trunk fuse panel i know is 12v switched for the B8 not 100% for the B8.5. You can go to your local auto store or even walmart and by a tap-a-fuse which will plug in with a wire lead, or splice one of the wires coming off.

[QuattroRocket]

I was trying to tap into the back of the panel but you are right a tap a fuse would be easier although it would accomplish the same thing. The real problem is most of the 3 fuse panels remain live, seemingly all the time ! I cant find anything that turns off when the car turns off (good old fashioned 12v test light hit live 12v on every block) ??? Car on, off, closed, locked. hood open, closed ... nothing seems to have it turn off ???

[B8_Jim]

I cant find anything that turns off when the car turns off (good old fashioned 12v test light hit live 12v on every block) ??? Car on, off, closed, locked. hood open, closed ... nothing seems to have it turn off ???

Wouldn't think the S5 is that much different. I taped my dashcam into the top "vertical" fuse on the front block on the drivers side. It is switched with the ignition.



Didn't look for others - this one worked. Of course this only has the hot wire installed - put the ground on the dash mounting bolt above (in the pic) with an extra nut.

[QuattroRocket]

Wouldn't think the S5 is that much different. I taped my dashcam into the top "vertical" fuse on the front block on the drivers side. It is switched with the ignition.

Didn't look for others - this one worked. Of course this only has the hot wire installed - put the ground on the dash mounting bolt above (in the pic) with an extra nut.

Ok thanks, auto parts store is closed and I am hitting the road tomorrow am so I guess the laser diffuser will have to wait until my return, probably safer that way anyways !

Thanks for the pic, helped a bunch to see what you were meaning, tapping the wire off the back of the panel is a PITA.

[dizzlesizzle]

the pic above is different from where i was referring to. I also couldn't find a switched 12v in that fuse panel. Here are a few shots of the trunk fuse box and red row of fuses i'm talking about.

[Green Neenja]

For future reference and in case someone else is looking for a switched 12v source, I tapped in to fuse #3 located in the panel on the left side of the dash today on a 2013 S4.

[abcha0s]

*** Bump ***

QuattroRocket - You didn't post a resolution? Did you ever figure this out?

As per the OPs first post, I am going crazy trying to figure this out.

The switched "Red Row" that dizzlesizzle is referring to in the A4/S4 b8 is MIA in the b8.5s. There is no red row of fuses. I've tested every fuse in the trunk fuse panels (that I am comfortable removing) and all of them stay on after turning off the car.

For my purpose, I am looking for a 12V switched line for a Remote Turn On lead for an aftermarket amplifier. The amplifier is in the trunk along with the speakers, so I would really like to avoid bringing any lines back from the front of the car. I am using (or at least hoping that I can) a TAPA fuse.

Thanks in advance!

[achilleas101]

do you have a multimeter? if not, i highly recommend getting one, doesn't need to be anything fancy, although i prefer digital. I got a $20 one from Advance Auto parts, and it's been immensely helpful. you can test out each fuse while it's on there without driving yourself crazy. Especially if you're doing electrical work, that's a must have tool.

if you were talking front of the car fuse panel on the driver's side, i could more directly answer your question (the entire left bank is switched), but i haven't touched the rear panel so i can't.

[infinkc]

*** Bump ***

QuattroRocket - You didn't post a resolution? Did you ever figure this out?

As per the OPs first post, I am going crazy trying to figure this out.

The switched "Red Row" that dizzlesizzle is referring to in the A4/S4 b8 is MIA in the b8.5s. There is no red row of fuses. I've tested every fuse in the trunk fuse panels (that I am comfortable removing) and all of them stay on after turning off the car.

For my purpose, I am looking for a 12V switched line for a Remote Turn On lead for an aftermarket amplifier. The amplifier is in the trunk along with the speakers, so I would really like to avoid bringing any lines back from the front of the car. I am using (or at least hoping that I can) a TAPA fuse.

Thanks in advance!

I had to use the location in the front fuse panel and run it back to the amp.

[abcha0s]

*** Bump ***

QuattroRocket - You didn't post a resolution? Did you ever figure this out?

As per the OPs first post, I am going crazy trying to figure this out.

The switched "Red Row" that dizzlesizzle is referring to in the A4/S4 b8 is MIA in the b8.5s. There is no red row of fuses. I've tested every fuse in the trunk fuse panels (that I am comfortable removing) and all of them stay on after turning off the car.

For my purpose, I am looking for a 12V switched line for a Remote Turn On lead for an aftermarket amplifier. The amplifier is in the trunk along with the speakers, so I would really like to avoid bringing any lines back from the front of the car. I am using (or at least hoping that I can) a TAPA fuse.

Thanks in advance!

To help future A4 b8.5 owners.

1. There does not appear to be any switched 12V fuses in the passenger side trunk.
2. I found an empty switched 12V in the driver side front - slot 13 in the first bank labeled Air Bag.
3. I had avoided the front fuse panel because I did not know how to run the wire to the trunk without removing the trim. It actually turned out to be much easier than I had anticipated. I was able to run the wire along the top of the car and out through the trim in the trunk without having to remove anything. I simply pulled back the rubber and gently fitted the wire behind the trim. No problem and the path took me all the way from inside the fuse panel and into the trunk.

Edit: I see that I actually used the same fuse as B8_Jim (Above). B8_Jim was nice enough to post a picture.

[Shimmy]

Does anyone know of a good switched power source from the passenger side fuse panel?

[dizzlesizzle]

Does anyone know of a good switched power source from the passenger side fuse panel?

What are u trying to get power for? i am not sure of the 12v switched power in passenger fuse panel, but I tapped into the homelink system for my radar detector which is 12v switched power.

[Shimmy]

What are u trying to get power for? i am not sure of the 12v switched power in passenger fuse panel, but I tapped into the homelink system for my radar detector which is 12v switched power.

Installing a BU camera and the "brain" for it requires 12v

[purelife]

Where is the right luggage compartment fuse box? I can't find it in the trunk.

[Wagoon]

Anyone found one in the trunk yet, I spent a few hours yesterday searching for one in my 2013 and the best I found was Switched 6v going to the Factory B&O amp.

I wish this could've been as easy as my 2010 which had a whole bank.

[Lamprey]

Anyone found one in the trunk yet, I spent a few hours yesterday searching for one in my 2013 and the best I found was Switched 6v going to the Factory B&O amp.

I wish this could've been as easy as my 2010 which had a whole bank.

As far as I know there isn't one on the 2013's. At least I've read that isn't. Additionally, I couldn't find one on my 2013. I had to go to the front.

[Kczach]

Be careful if you add a fuse or tap into any wires and warranty claim denials. I had added a fuse on my 11 S4 and when they were having problems connecting to my car to reset the service reminder they tried to blame it on my tapping into the rear view mirror fuse.
Some of these SA's feel that only they can touch a car otherwise if anything goes wrong it is your fault. As a result I deal with another SA who is a little more relaxed and doesn't have a rod up his butt to measure the amount of grease in his hair.

[myrison]

Anyone found one in the trunk yet, I spent a few hours yesterday searching for one in my 2013 and the best I found was Switched 6v going to the Factory B&O amp.

As far as I know there isn't one on the 2013's. At least I've read that isn't. Additionally, I couldn't find one on my 2013. I had to go to the front.

I'm here to confirm there is not one in the rear passenger side fuse banks for the 2014's either. Just in case anyone else is stubborn like I am and feels compelled to test every fuse, hopefully this saves you the time. @abcha0s, thanks for the tip on how to guide the wire from the front. I did so as well and it was quite easy as you explained.

[dropshadow]

I wasted a couple hours last night on this same endeavor ... until I searched google and found this thread. I was trying to wire a rear dashcam to a switched fuse, but of course, couldn't find one in the rear fuse block. I ended up tapping into the wiring for the rear cig lighter/accessory plug and grounding on the chassis. Works like a charm. The camera now powers up with the car and turns off about a minute after the ignition is shut off.

[Wagoon]

I wasted a couple hours last night on this same endeavor ... until I searched google and found this thread. I was trying to wire a rear dashcam to a switched fuse, but of course, couldn't find one in the rear fuse block. I ended up tapping into the wiring for the rear cig lighter/accessory plug and grounding on the chassis. Works like a charm. The camera now powers up with the car and turns off about a minute after the ignition is shut off.

I did actually find one eventually but never followed up here after the fact. There is a switched 12v in the rear passenger side, under one of the relays. Not sure i took pictures, but would not be hard to get one if anyone needs it still.

[SteveYem]

I did actually find one eventually but never followed up here after the fact. There is a switched 12v in the rear passenger side, under one of the relays. Not sure i took pictures, but would not be hard to get one if anyone needs it still.

Yes, please do. I currently have my aftermarket subwoofer amp and line-out converter connected to the switched +12v in the front driver side fuse panel in the cabin, but I would have preferred to connect it locally in the trunk.

@dropshadow: That's interesting that the power remains on for a bit after the ignition is switched off. That's exactly how I want my subwoofer amp to behave (so that the full sound continues to play after I turn the car off), but as it is currently the amp shuts off immediately with the ignition using the switched +12V from the front driver side fuse panel. I suppose they wired the cig lighter circuit this way as a 'convenience' feature for anyone who needs to light a cigarette within a minute of shutting off the car...?
EDIT: How/where did you route your wiring from the rear cigarette lighter into the trunk?

[doug97gxe]

Yes, please do. I currently have my aftermarket subwoofer amp and line-out converter connected to the switched +12v in the front driver side fuse panel in the cabin, but I would have preferred to connect it locally in the trunk.

@dropshadow: That's interesting that the power remains on for a bit after the ignition is switched off. That's exactly how I want my subwoofer amp to behave (so that the full sound continues to play after I turn the car off), but as it is currently the amp shuts off immediately with the ignition using the switched +12V from the front driver side fuse panel. I suppose they wired the cig lighter circuit this way as a 'convenience' feature for anyone who needs to light a cigarette within a minute of shutting off the car...?
EDIT: How/where did you route your wiring from the rear cigarette lighter into the trunk?

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[eightamrock]

I did the same thing this weekend.

One question, does anyone know what this relay is connected to? Im worried about taking it in for service at the dealership and them voiding warranty on something crazy because I tapped the 12v remote here.

Also, does anyone ever fuse their remote wire? I was thinking about putting a 1 amp fuse on this, more so because its on a relay and not a fuse.... thoughts?

[doug97gxe]

I did the same thing this weekend.

One question, does anyone know what this relay is connected to? Im worried about taking it in for service at the dealership and them voiding warranty on something crazy because I tapped the 12v remote here.

Also, does anyone ever fuse their remote wire? I was thinking about putting a 1 amp fuse on this, more so because its on a relay and not a fuse.... thoughts?

i've been running this setup since September .. the car has been in for service once.. no one said anything.. and its easy enough you can remove it if you want.. never had a problem none fuse either

[eightamrock]

i've been running this setup since September .. the car has been in for service once.. no one said anything.. and its easy enough you can remove it if you want.. never had a problem none fuse either

Thanks for the note. Ill just pop it out if I get paranoid about it. Still curious what this relay does though... can't seem to find it anywhere online. Admittedly, I have not checked the manual yet.

[monatex]

i've been running this setup since September .. the car has been in for service once.. no one said anything.. and its easy enough you can remove it if you want.. never had a problem none fuse either

I have a 2009 Audi S5, been having this same issue, can't find a switched for the turn on lead. The only one I have found is ONLY switched when the car is running, which is the red fuse block in the passenger side of the trunk, it will not provide 12v power when the key is in the ignition. Can you explain in more detail how you tapped into this relay? Did you just bend a wire around one of the pins and put the relay back in? Which pin is the one to use? Do you think it would work the same on my 09 S5? Did you have to take the negative lead off of the batter or can you just pop the relay out and pop it back in?

[Smac770]

There's plenty of term 15 access (well, unless it's a B8.5 it seems). The black fuse carrier on both ends of the dash are term 15. As for the red fuse carrier in the right rear, it'll vary.
Through MY09, slots 1-4 are term 87 (engine on) for the 12v sockets, slots 5-12 are term 15.
For MY10-MY12, slots 1-6 are term 87 and 7-12 are term 15.
For MY13+ (B8.5), it appears red is not even used, and all of fuse panel F is term 30. Term 15 devices, like the lane change assist radars, are powered from the dash fuse panels. Seems like a lot of extra wiring so to not have to populate panel F red.
While these are for the 8K (A4); I don't see why the 8T (A5) would be significantly different.

[monatex]

There's plenty of term 15 access (well, unless it's a B8.5 it seems). The black fuse carrier on both ends of the dash are term 15. As for the red fuse carrier in the right rear, it'll vary.
Through MY09, slots 1-4 are term 87 (engine on) for the 12v sockets, slots 5-12 are term 15.
For MY10-MY12, slots 1-6 are term 87 and 7-12 are term 15.
For MY13+ (B8.5), it appears red is not even used, and all of fuse panel F is term 30. Term 15 devices, like the lane change assist radars, are powered from the dash fuse panels. Seems like a lot of extra wiring so to not have to populate panel F red.
While these are for the 8K (A4); I don't see why the 8T (A5) would be significantly different.

I'm not sure what you mean by "Term 15"? In my 09 S5 using a multi-meter, I cannot find any 12v switched power either in the front boxes or in the rear boxes that are on when the key is in the ignition. The only ones that provide switched power are the slots in the red fuse box in the back right but the engine has to be running. It is so frustrating.

[Smac770]

term 30 = always on 12v
term 31 = ground
term 87 = relay switched 12v, engine on (87 is just the output pin on a Bosch relay, but in this context, it generally means engine on output)
term 15 = relay switched 12v, ignition on

Go to the fuse panel C (left end of dash). With the key off / engine off, measure the voltage across the test pads of one of the fuses in the black column 1 and the brown column 2. You should measure 0V on the black column fuse and 12V on the brown column fuse. Then turn on ignition, lights on the dash should come on, radio should come on. Now you should measure 12V on the black column fuse. If you don't, turn the engine on. Does now the black column fuse show 12V? If that's the case, maybe you have an issue with the term 15 relay.

You're saying you observe the same switching behavior for the the fuse 1 in the fuse panel F (back right) red fuse 1 as for red fuse 12? It would be best if any actual 8T owner ever bothered to get the workshop manuals and wiring diagram documents for an 8T from erwin.audiusa.com. But I still find it highly unlikely the 8T is wired that different from an 8K.

[monatex]

term 30 = always on 12v
term 31 = ground
term 87 = relay switched 12v, engine on (87 is just the output pin on a Bosch relay, but in this context, it generally means engine on output)
term 15 = relay switched 12v, ignition on

Go to the fuse panel C (left end of dash). With the key off / engine off, measure the voltage across the test pads of one of the fuses in the black column 1 and the brown column 2. You should measure 0V on the black column fuse and 12V on the brown column fuse. Then turn on ignition, lights on the dash should come on, radio should come on. Now you should measure 12V on the black column fuse. If you don't, turn the engine on. Does now the black column fuse show 12V? If that's the case, maybe you have an issue with the term 15 relay.

You're saying you observe the same switching behavior for the the fuse 1 in the fuse panel F (back right) red fuse 1 as for red fuse 12? It would be best if any actual 8T owner ever bothered to get the workshop manuals and wiring diagram documents for an 8T from erwin.audiusa.com. But I still find it highly unlikely the 8T is wired that different from an 8K.

I'll test again tonight after work but I have tested all of the fuse boxes out with a multimeter and can find NONE that are not constant 12V except the red fuse box passenger side trunk. That one only has 12V when engine is running. I'll check again with key out, key in, etc., tonight. Thanks.

[monatex]

term 30 = always on 12v
term 31 = ground
term 87 = relay switched 12v, engine on (87 is just the output pin on a Bosch relay, but in this context, it generally means engine on output)
term 15 = relay switched 12v, ignition on

Go to the fuse panel C (left end of dash). With the key off / engine off, measure the voltage across the test pads of one of the fuses in the black column 1 and the brown column 2. You should measure 0V on the black column fuse and 12V on the brown column fuse. Then turn on ignition, lights on the dash should come on, radio should come on. Now you should measure 12V on the black column fuse. If you don't, turn the engine on. Does now the black column fuse show 12V? If that's the case, maybe you have an issue with the term 15 relay.

You're saying you observe the same switching behavior for the the fuse 1 in the fuse panel F (back right) red fuse 1 as for red fuse 12? It would be best if any actual 8T owner ever bothered to get the workshop manuals and wiring diagram documents for an 8T from erwin.audiusa.com. But I still find it highly unlikely the 8T is wired that different from an 8K.

I have 3 fuse strips front drivers side, a black, brown and red. Red is all constant 12v, both black and brown ONLY have power when car is on, no power when car is off or when key is in the ignition.

[Smac770]

What do you mean "car on", you mean engine running?
Ignition on, term 15, means the DRL and radio and climate system and such are on (or can be turned on/off), engine can be running or not.
You have to press the key, foot not on brake, to turn on ignition, term 15, without also starting the engine. In case we're missing each other in semantics.
Take the HomeLink buttons, they are on fuse 3 in the black column on the driver's end of the dash, on term 15. So they stop working after you turn the engine off. If you get in the car, they will not work. If you then turn on ignition (but not the engine), they will now work.

Also, the brown actually has a mix of terms present. 1-3 are term 87, engine on. 4 is term 15, ignition on, 5-12 are term 30, always on. But that's on my 8K. Using the red rather than brown as a term 30 counter example to the term 15 black is better.

[wrxkyle]

What do you mean "car on", you mean engine running?
Ignition on, term 15, means the DRL and radio and climate system and such are on (or can be turned on/off), engine can be running or not.
You have to press the key, foot not on brake, to turn on ignition, term 15, without also starting the engine. In case we're missing each other in semantics.
Take the HomeLink buttons, they are on fuse 3 in the black column on the driver's end of the dash, on term 15. So they stop working after you turn the engine off. If you get in the car, they will not work. If you then turn on ignition (but not the engine), they will now work.

Also, the brown actually has a mix of terms present. 1-3 are term 87, engine on. 4 is term 15, ignition on, 5-12 are term 30, always on. But that's on my 8K. Using the red rather than brown as a term 30 counter example to the term 15 black is better.

there is another situation of ignition off but (bleedover?) power on, when you turn the car off but don't open the door. the ecu is not on(can't pull codes) so ignition is off but radio and some things are still on, but the relay people grab off of in the trunk does shut off in that case but op might want power that continues to be on in that circumstance. i THINK the cig lighter is still on then as well so that could be a solution for a remote source.