Tapping onto a tape deck audio circuit for external Aux output

I've got an idea I'd like to experiment with.

I have a stock car audio tape deck (Subaru Outback). I don't use the tape deck other than with the tape adapter to plug in my ipod.

My idea is this: Id like to use an iPod Auxiliary cable adapter like THIS:

Newegg.com - Isimple IS75 Universal iPod Cable

...sorry for some reason the PC at work blocks the use of the html/edit buttons above (i'll fix the link when I get home).

I want to use the rca jacks from the adapter to tap into the tape deck's audio circuit. Obviously I'll have to cut the rca ends off to solder onto the circuit board.

Does anyone see a reason this won't work?

Anyone ever attempt a mod like this? I sort of don't know where to start other than probing around on the deck looking for an audio signal somewhere.

Lets start with that; more questions to come i'm sure...

The easiest place to tap into the audio is usually on the volume pot.

That is almost always after the cassette head preamp and before the output amp.

That used to be true but in the last 15 years or so you have to check to see if the volume is voltage controlled.

Much easier to buy a cheapo ($5/£5 ish) FM Modulator and tune your radio in.

We got a cheapo one years ago and it was remarkably good.