I recently installed 2 x920bt's in our vehicles. It's a great unit. In my wife's 2005 Navigator she has the parking assistance sensors (the ones that beep). I hooked up the mute signal output from the sensor module to the yellow/black mute wire (the mute wire is in its factory location. I added a wire and pin for the GPS/DVD bypass.) and the HU is in full time mute. It seems the sensor module is continuously supplying voltage to the mute wire. I cut the mute wire and the full time mute problem was solved. I would like the reverse sensors to mute the HU as it did on the factory HU. So, my question is how much voltage does it take to trigger the mute function on the x920bt through the mute wire? Also, does anyone think this situation can be remedied by installing a resistor inline to the mute wire? Thanks in advance.

It all depends on the circuit. I would probably just run the mute to the reverse lead, it would save yourself a lot of time. Basically whenever the car is in reverse, it would be muted.

You could in theory also tap the mute into the actual "beeper".

How many volts is that sensor outputting? U need to check it when is active and not active to see what changes. The Mute input on the AVIC probably wants to see 12V to enter enter that state.

Thank you for the input. I'll check the voltage output from the sensor module. It does make sense to go straight to the beeper as the source or, secondarily, to the reverse lead. I'll keep you posted.

i agree with jason, tapping the mute wire into the reverse wire wire would be the best option(as lond as the polarity was corect), as the factory back up module probably doesnt have the same signal that the AVIc would like to see.

does the AVIC need to "see" 12v or ground?

Ok, so I finally had time to get back into the Navigator. Here's what I found:

The park assist sensor module puts out .01 volts in park (yes .01 volts), .04 volts in reverse and .05 volts when the sensors detect an object in reverse. Effectively no voltage. (I did make sure my multimeter was set for the correct level of DC voltage when I saw those numbers)

I connected the mute wire to the reverse lamp light circuit. When the car is in park, neutral or any drive gear the volume is attenuated (muted) but when the car is in reverse and the reverse lamps are lit the volume switches to regular (or non-attenuated).

It would seem that the AVIC mute wire is looking for ground as it probably gets in the two wired scenarios thus far. I'm thinking a relay tripped by the reverse lamp circuit switching the mute wire to ground may get me where I need to be. Any thoughts?

yes, just use a relay to reverse the polarity.

Thanks 1loudls. I'll let you know how it turns out.

great