2008 S5 B8 trunk fuse box

[S5withproblemz]

Looking to see if anyone has the label sheet for these fuses in the trunk (passenger side / American) or reference picture ? Chasing a parasitic leak 308713


08’ S5

Sent from my iPhone

[Smac770]

https://cardiagn.com/current-flow-diagram-07-17-audi-a5/
or
https://cardiagn.com/audi-a5-coupe-8t8t38ta-ewd-from-june-2007/

They might be the same document, I didn't open them. But the fuse assignments should be in section 802 of the wiring diagram document.

Note, fuses for the B8 come in three eras: >MY09 (aka B8.0 MMI 2G era), MY10-MY12 (aka B8.0 MMI 3G era), and MY13-MY17 (aka B8.5 era). Any fuse diagram that's not clearly labeled as which of the three it's for is not useful.

As for your image, you have so few fuses (I assume from the fuses present you have MMI 2G?):

B1, 5A - J502 TPMS
B5, 5A - E538 EPB switch
B7, 30A - E540 EPB
B8, 30A - J393 BCM2 (expect this as power source for taillights)
B10, 30A - J393 BCM2 (expect this as power source for taillights)
B11, 20A - J393 BCM2 (expect this as power source for other circuits)

C3, 7.5A - R radio, J401 navigation drive, R146 Sirius tuner
C4, 30A - J525 amp
C5, 5A - J523 MMI 2G
C7, 30A - J540 EPB
C9, 30A - J387 front passenger door control module
C11, 15A - J387 front passenger door control module

D1, 15A - 12v socket
D2, 15A - 12v socket
D4, 15A - 12v socket (this is the one in the dash)
D12, 5A - J234 airbags, E3 hazard switch, J706 PODS, K145 passenger airbag disabled lamp

The 12v socket fuses are powered by one of the relays back there, and is only on when the J393 commands it on (when engine running).

If you measure a current flow issue when the car has been locked for an hour back there, I imagine it'll be the radio, the amp, or the EPB (two 30A for the EPB, one for each rear motor).

[S5withproblemz]

https://cardiagn.com/current-flow-diagram-07-17-audi-a5/
or
https://cardiagn.com/audi-a5-coupe-8t8t38ta-ewd-from-june-2007/

They might be the same document, I didn't open them. But the fuse assignments should be in section 802 of the wiring diagram document.

Note, fuses for the B8 come in three eras: >MY09 (aka B8.0 MMI 2G era), MY10-MY12 (aka B8.0 MMI 3G era), and MY13-MY17 (aka B8.5 era). Any fuse diagram that's not clearly labeled as which of the three it's for is not useful.

As for your image, you have so few fuses (I assume from the fuses present you have MMI 2G?):

B1, 5A - J502 TPMS
B5, 5A - E538 EPB switch
B7, 30A - E540 EPB
B8, 30A - J393 BCM2 (expect this as power source for taillights)
B10, 30A - J393 BCM2 (expect this as power source for taillights)
B11, 20A - J393 BCM2 (expect this as power source for other circuits)

C3, 7.5A - R radio, J401 navigation drive, R146 Sirius tuner
C4, 30A - J525 amp
C5, 5A - J523 MMI 2G
C7, 30A - J540 EPB
C9, 30A - J387 front passenger door control module
C11, 15A - J387 front passenger door control module

D1, 15A - 12v socket
D2, 15A - 12v socket
D4, 15A - 12v socket (this is the one in the dash)
D12, 5A - J234 airbags, E3 hazard switch, J706 PODS, K145 passenger airbag disabled lamp

The 12v socket fuses are powered by one of the relays back there, and is only on when the J393 commands it on (when engine running).

If you measure a current flow issue when the car has been locked for an hour back there, I imagine it'll be the radio, the amp, or the EPB (two 30A for the EPB, one for each rear motor).

You’re awesome thank you, unfortunately my MMI isn’t working right now so I can’t access that to see. I’m almost positive the draw is from my MMI, it cuts on the Home Screen then cuts off, assuming it’s still running in the background


08’ S5

Sent from my iPhone

[Smac770]

There's no need to be guessing. Manually latch the trunk lid (so the car thinks it's closed but it's still open), then lock the car and wait an hour. Then test the voltage drop across each of the fuses and look for any with any voltage that translates into excessive current draw (charts on the Internet exist for translating voltage drop to current draw for different fuses). But it could just as easily be a bus waking constantly when it should be sleeping. This wouldn't be uncommon with the radio or amp unit if it's been damaged from water intrusion. But it could just as easily be anything else in the car causing bus rewake or excessive quiescent draw.

[S5withproblemz]

There's no need to be guessing. Manually latch the trunk lid (so the car thinks it's closed but it's still open), then lock the car and wait an hour. Then test the voltage drop across each of the fuses and look for any with any voltage that translates into excessive current draw (charts on the Internet exist for translating voltage drop to current draw for different fuses). But it could just as easily be a bus waking constantly when it should be sleeping. This wouldn't be uncommon with the radio or amp unit if it's been damaged from water intrusion. But it could just as easily be anything else in the car causing bus rewake or excessive quiescent draw.

I’ll be purchasing Ross tech soon, did have it at the shop recently and buddy told me the bus was tripping for the parking brake, but suggested the MMI cause it wasn’t working so I figured I’d start there. Should have time tomorrow to start my diagnostics, thanks again, I’ll keep ya posted


08’ S5

Sent from my iPhone

[Bandiz]

Looking to see if anyone has the label sheet for these fuses in the trunk (passenger side / American) or reference picture ? Chasing a parasitic leak 308713


08’ S5

Sent from my iPhone

here is fuse box diagram that I found: https://fubox.net/audi/a5-8t-8f-2007-2016/#Luggage_compartment

it looks like the same as your posted fuse box pic:
https://fubox.net/wp-content/uploads/2024/12/Audi-A5-2010-2016_lug_10.jpg