Panscrank

Turns out I replaced fuse 24 and all is good. Fuse diagram confusing as car is RHD but understand it now

I have a 2004 3.2 8p. RHD. The cigarette lighter port does not work. I took it out and put a multimeter on it and it reads 0.36v. Fuse 24 is a red 10 amp fuse on my fusebox, so I tried changing that for a 20 amp fuse and a Headlight level warning came up on the dash. So this led me to think perhaps I got the fuse wrong but all advice online keeps saying 'change fuse 24' There are three wires on the plug that connects to it; I could only get that multimeter reading connecting as seen in these pics, otherwise it read zero. (This was with the car ignition on) Any help, greatly appreciated.

Can anyone help? Surely there are others who have installed an aftermarket 7" stereo to an A3 and have solved this issue previously?

Hello there. 1st post. I did check through the search but couldn't find a solution. I have just purchased a 2004 A3 3.2 3dr with the Bose sound system. I bough this aftermarket 7" Alpine unit https://www.amazon.co.uk/dp/B09RSFQ1QC?ref=ppx_yo2ov_dt_b_fed_asin_title And this fascia adapter: https://www.ebay.co.uk/itm/281902518707?fits=Car+Make%3AAudi|Model%3AA3&_skw=CT24AU15+Audi+A3+8P+2003-12+Car+Stereo+Radio+Double+Din+Black+Fascia+Facia+Panel&itmmeta=01J82PXG16VC0RB9NN39CCB2SM&hash=item41a2b311b3:g:2qEAAOSwzZFd75r9&itmprp=enc%3AAQAJAAABMHoV3kP08IDx%2BKZ9MfhVJKnZ%2FGaDWuDC0q0gZe267IGTc9xIDhTP%2B9zk8PcjSpqBFT4sy0%2B4TANww4b%2Bd%2BnXMe%2Bg1IcMhVWK2x3d%2Fn2QzGk%2FebQQwSuMLt1IYYTJdSu0wnN2uYFsxI2i8pk2aQHFJrPCkpF2k9m46IkD5%2BU90g73yDTeKtqJZ3KUDoC9hvNLQ%2FQnid%2FewMDRHK%2F1%2BbaHwuE2aBg9sGGVNVqQb60vicphHMfAms9QHSwkGpCJCEBevBJ0ipYE3uWeFQsX68mORXB0EICXo9ofi5BIoH%2FpfkvqAwuzXIPWsc2W2XMhcuRoLNX2%2FxUI35UnhsFBjljlhiFjyJSYn9fzcewEDmkrRdxh1kqQCMgTB6JVr1kqXh652HeAXWb9tiNCH8SnID6%2FLP8%3D|tkp%3ABFBM2oD21sBk The fascia fits into the space beautifully but this stereo I have bought is way too small to sit snugly in there. Do I need to purchase a double din cage, as there wasn't one with the unit. And if so, is there a specific one I need? Do I need a different fascia? Looked around everywhere but all i can see is ones like the one I bought already. Any help greatly appreciated.