Thread: Audio signal experts - please help (two line-level inputs wired in parallel)

Hi guys,

I hope someone with more electrical expertise than I have can solve a problem I have. I've done extensive searching with no luck, but no answers yet. Here is my situation:

I have a BMW e39 which is pre-wired for a cell phone. I have sucessfully installed a cell phone carkit and everything works as it should.

There are two wires from the carkit that carry a line-level audio, which I've connected to two wires in the center console. The cell phone audio is now heard nicely from the car stereo speakers (somehow it is routed into the stereo amplifier).

Here's the tricky part.... I have a portable GPS (Garmin Quest) which is a nifty little unit and has a small speaker that speaks turn-by-turn voice instructions. I have "tapped into" the two wires leading to the little speaker and hooked them up to where the cell phone carkit is installed.

--> If I disconnect the cell phone carkit audio wires, and connect the GPS wires, I hear the nice GPS lady's voice coming out of the stereo speakers -and- the little speaker in the GPS itself (this is all good - sounds great!). But if I hook up both the cell phone carkit and the GPS (in parallel) then I only hear the cell phone.

When they are both wired together it is like the GPS audio circuit shuts down - I don't even hear the GPS voice coming out of its own little speaker. Maybe there is some signal or voltage being carried by the cell phone carkit that feeds back into the GPS and causes this to happen?

My only idea is possibly a diode - so that the GPS audio will only feed out into the car - but I have no idea where to start, what type or rating of diode to even try.

Any ideas? It would be great to hear not only my cell phone but also my GPS through the stereo speakers!

Thanks,

Paul