When fishing around in my M03 WRX's boot, looking for somewhere to wire in a fag-lighter socket to power an electric cool box, I found a strange box I couldn't identify.

It's under the roof of the boot, and is a vented box about three inches square. Removing the cover shows four coils of very thick copper wire, with heavy duty red and black wires leading in one side and out the other. None of the wires seemed to be live with the ignition on or off.

Can anyone tell me what it's for?

music amp?

something to do with the rear screen radio ariel... if you strip out all the back seats/plastics etc... there are some other clarion bits and bobs back there as well.

Richie.

It's a power conditioner for the heated rear window.

The amp for the aerial is in the roof lining.

ah Nick.. I was close though ;)

Richie.

Thanks for that - explains why it's got such thick wires, and why none of it was live.

Next question - why does the power need to be conditioned for the rear window heater? One would have thought a heater would heat whatever kind of electicity you put through it.

I'm guessing that if you put spikey currents through it, then it's going to act as some kind of transmitter and mess up your radio reception. Is that it?