The tape deck on my Volvo 240 was dead when I bought it. I decided to take it apart to see if if I could fix it, only to find some pretty horrendously broken plastic gears and bits. I couldn't handle having an ugly aftermarket radio, so decided to put in a "line in" for an ipod/cd player/portable record player/etc...

Ideally, I wanted to tap into the circuit in between the tape deck and the amplifier. I didn't manage to find this exact spot but am by no means an expert. The easiest thing was to put my line in in between the tape head and the and tape deck preamplifier. There is a mini wiring harness between the two, so I just unplugged it, cut it and solder a shielded cable to it. Since the tape preamp is expecting a very weak signal I put an attenuator (just a bunch of resistors - a transformer would have been nicer) right where the cd player/ipod plugs in. A little EQing is necessary to get perfect sound (bass down, treble up), but this thing sounds great, even loud enough to cover up that rattling heat shield!

The best part is that when you want to listen to the "Aux In", you simply push in a tape - that triggers the radio to turn off and the tapedeck stage of the stereo to activate, so you still get all the tactile pleasure of handling a cassette.

I also disabled power to the motor so I wouldn't have to listen to broken gears turning.

Maybe somebody with greater knowledge could point out a better spot in the stereo to tap into?