I'm trying to tap into the fuse box in the trunk in order to run a remote turn on wire to my amp, but I'm having trouble finding one that is on only when the car is started. Has anyone else tried to setup an after market amp turn on in this way? Thanks for any info.

 

So after testing a few fuses, I found the only fuse that turned on and off with the ignition is F25 in the trunk. It is for the fuel pump, its clear, and 25A.

For anyone else looking to do some aftermarket stereo work, you can use the speaker output from the factory amp for the input on your aftermarket amp. Do this by getting an amp with "speaker level inputs" such as the Polk Audio PA660. Also use an "Add-a-circuit" fuse you can get from an auto parts store for your remote turn on wire. Be sure to ground the black wire coming from the speaker level input adapter to the chassis to get rid of any "whine" you hear at low volume.

Wires you need to look for coming off the factory amp in trunk:
(Speaker Location): (positive wire) - (negative wire)
Left Front Speaker: white - white/brown
Right Front Speaker: white/purple - white/orange
Left Rear Speaker: white/green - brown/yellow
Right Rear Speaker: brown/white - brown/blue

Subwoofer is under the black plastic tub which is under the spare tire. There are 4 wires going to it. Two for each voice coil (3ohm voice coils.) Factory amp output of 70W-100W rms per coil.

 

Glad you sorted it out. Good information!

 

My Jaguar XF 2011 was unfortunately delivered without the subwoofer that my previous XF 2009 had (and also no spare tire wheel is there!). I have therefore purchased an original Jaguar subwoofer box and connected it to the plug that already was there on the right side of the boot. But no sound will be heard. Maybe it is as simple that the fuse that controls this subwoofer is not fitted in the fuse box? And if that is the case, which fuse can it be?