and this one:
For those of you trying to install a new head unit in your Z, but keep the existing factory navigation system, and keep the voice, the info below will work ! THis is what I did, and it works great, just like the factory navigation system does. Keep in mind that you will have to have a Mute capable head unit, and you will have to wire a seperate speaker for the nav voice. A small price to pay for the much better sound you will get out of an aftermarket head unit.
Anyways, here is what I did:
The output of the NAV system is about 7.5-9 volts. This is not enough voltage to trip a standard 12 volt (30A) relay. So, what I did was this. You have to setup a 2 stage system, composed of a transistor and 12v relay, to switch the mute circuit on a new head unit.
Parts I used:
1. Potter and Brumfield 12V Relay (Bosch will work too)
2. TIP31 high power NPN Transistor (Radio shack sells it)
3. Various length wires and crimp-type connectors
4. 1 kohm resistor (1/4 watt)
NAVI-SYSTEM WIRE MAP:
Mute wire from NAVI control to head unit - R/B
NAVI earth ground - B/P
NAVI Voice input + L/B
NAVI Voice input - W/B
All transistors consist of a Base (B), Collector ©, and an Emitter (E). The pacakge will tell you, if you buy it from ratshack, or look online for a datasheet for your transistor. THis circuit will work for an NPN only. A pnp transistor will be wired differnetly, so make sure you get the proper parts !
1. Wire Mute (R/B) from NAVI control to the transistor Base (B) through a 1kohm resistor (Limits the current so you don't fry the TIP31).
2. Wire the Emitter (E) to vehicle ground
3. Wire the collector © to postion 85 on 12V relay
1. From 3 above, wire the output of the collector to position 85 of a 12v relay.
2. Wire postion 86 to 12v switched by the ignition (only on when key is on)
3. Wire postion 30 of the 12v relay to vehicle ground
4. Wire positon 87 of the 12v relay to mute input on the new head unit.
5. Position 87a is not connected
Here's what happens:
When the voice control turns on for the navi system, it send the R/B wire high (7.5 volts). This voltage triggers the transistor to open up, and essentially provide ground to the relay. Once the relay is grounded, the relay is energized, and switches the constant ground (suppleid by terminal 30) to position 87, and supplies a ground signal output from the 12v relay. This ground signal MUTES your new head unit. THat's all...simple circuit, great results !
Don't forget that you will have to add a seperate speaker for navi voice under your seat, and run the 2 voice output wires from the navi control to this speaker. If you mount it under the driver's seat, you may have to turn the volume up slightly to hear it...
Good luck, and I hope this helps those who are adding aftermarket headunits to a Z with factory navigation...