Eh? I'm a bit confused here. The illumination is connected to the headlight switch? I thought it was connected to that dimmer that adjusts the brightness of the dashboard, so when the dash is set to be dimer or brighter, the Z2 controls also get dimmer or brighter. I guess the difference is that being connected to the headlight switch is just two states. I thought this one was either a pulse width modulation, or a DC level. Please understand that I don't actually have an AVIC-Z2 yet and have not installed one - I made this assumption because the steering wheel controls output the illumination/dimmer as a signal to the headunit.
8axled: I actually made that same exact assumption when first doing my install (mind you, don't work on car electronics much). Then I realized the factory GM Illumination is a binary. The configuration of Z2 allows for 2 states - night (Hi+) and day (Lo-) with corresponding color setup...
rjedlich, is right. The Z2 and Z1 only have 2 different states. Night and Day. And it watches the illumination wire. This wire can function in 3 different ways.
1. 0V day (lights are off) and 12V night (lights are on) - depending on where you tap in, there is a wire that functions like this in every car.
2. 0V day (lights are off) and variable DC voltage night (lights are on and this is the dimmer/brightness of the interior) - not very common any more, the circuitry for this to drive the interior bulbs is large, and energy wasting (you get a lot of heat from something like this).
3. 0V day (lights are off) and an Pulse width modulation Night - when you turn on the headlights, the interior lights are dimmed by turning them on and off 1000 times per second, the longer they are on vs off the brighter they will appear and the time this takes is too quick for humans to perceive a flicker.
I know the Avic Z will work off 1 or 3. I never tried 2. I would not assume it would work. My circuit I made for the Z1's would work off any of these, but I don't know the internal of the Z2 to know if it would react to a DC voltage level lower than 12V. Which is why they say to hook it to ILLUMINATION not DIMMER.
Thanks Ducatiboy, I couldn't put that advanced string of thought together myself. I figured its hot (+12) or null (no charge / no ground). So in my mind I figured there could be 3 states: +12, -12, Zero... (Hi, Lo, Null) Guess I gotta brush upon my engineering textbooks
Poor wire harness now has many crimp connector patches
Time for a breadbox back there...
No problem, they usually take a resistor and pull the input wire to a known state they want. high +12V or low/ground (0V). Then the wire you hook this to would have 2 states, high and low. If the input wire is normally pulled low (in the case of the illumination wire, notice that if you don't even hook that wire up it assumes day mode/lights off/wire at 0V) and you hook it to something that's normally low/ground/0v it won't change anything. In the case of the ILL wire, you have to apply voltage to it (maybe +12, maybe it would work off of something lower, I never tried) to get the Avic Z to see the change and do something.
I don't know if anyone has tried this yet, but has anyone tried to load the avic z1 bluetooth update disk into the z2. It updated the bypass for the pre July z1 units maybe it will do the same for the z2. (sorry if this was already mentioned but just throwing some ideas out)
Yah, I think it has. I don't think it will take the update. The update is for the Z1. We have tried taking those files and loading it manually and the Z2 won't boot. If you take every single file from the Z1 and put it into the Z2 and over write all the files, it will turn into a Z1 and be bypassed like a Z1. But it seems to have checks for "appropriate files" upon boot or they changed the software so that the files that called upon boot which were from the Z1 are missing a function call or something which causes a failure. I'm still believing there is a file in there some where we can change to enable the bypass.
