Stock deck to trigger mute line?

I've had my empeg installed for a while, sitting on top of my dormant stock head unit which is supposed to be used for radio and CDs. Needless to say, hooking it up hasn't been a high prioity, but I've been thinking I should get around to it while I've got some time.

Yesterday it occured to me that I should be able to have hijack switch to aux in when the telephone line goes high or low, which seem the logical thing to do for the head unit, except that I don't know what line I could use from the stock deck to trigger the line. Any Ideas? The car has a built in antenna, so there isn't an antena trigger line... If worst comes to worst I'll switch manually, but what's the fun in that?

Matthew

You could use the stock deck's Amp Remote wire if it has one. If it doesn't have one, there might not be anything you can use.

You could hook up a circuit to the line outputs on the headunit too, so that when a defined level of audio is present it will trigger the mute line.