2005
w/ BOSE
w/o ONSTAR

Preface:
I was inspired to take on the tablet (Samsung Galaxy Tab 2) install after reading the what users blazinblue and SDB_FTW did in this thread. I was planing on wiring the system like blazinblue, but he is kinda MIA atm; so I would like to know what the audio aficionados here think.

I have installed head-units/amps/speakers in my older cars. Some of them did not have very good labeling, but nothing a voltmeter couldn't fix. This car is a new level of complexity that is not very friendly to the amateur installer.

My goal is to efficiently hook the tablet into the existing Bose system without wasting money on unneeded harnesses and chime modules. Ideally running everything through the Metra 70-2003 24 pin harness (I need to rewire a few pins, not a big deal).

Question 1: Is the chime module absolutely required? My original research on it made it sound like it only controlled warning chimes. Major errors should be felt when driving and/or pop up on the HUD (please see instrument panel message); making the chime a secondary safety function that is not worth 100 bucks to me. Now I'm reading something about a Class II data bus in GMs after 02 (depending on model generation). I have not found how this affects the C6 in particular though. If it is needed, is C2R-GM24 still the best module for BOSE w/o onstar?


Question 2: How do I wire a relay into the system to make the power turn on and off with the acc/ignition button (if a relay is the correct way to do this)? The 30/40 amp spdt relay has 6 wires, but I only see 2 or 3 on the harness that I could wire into. B1 for constant ~22v power and A1 throws 2 spurts of ~3v when acc/ignition is turned on and 2 more when turned off. I read B3 sends a digital signal, but I couldn't pick up anything on the voltmeter.

(thanks to markcz for the source of this picture)




Question 3: Will this set up work for getting proper volume through the BOSE system? The ouput will be as follows (hopefully):

Tablet 3.5mm jack fed into a ground loop isolator then split into RCA left and right channel then fed into a Bybyte Quad 7850 amp and finally wired into the low level outputs of the harness (A8 - A11 and B8 - B11).




Thank you kindly for the help.

 

c2rgm24 is best option, will play chimes, gives you RAP controlled switched power trigger, and has RCA plugs wired to oem amp (a few cables and no splices needed).

Without c2r, you'll have to get switched power from a fuse in footwell, it isn't present at the HU plug. IIRC heated seat is popular and I believe windshield wipers works also. Wherever you get the trigger, connect it to B3 so you power up the oem amp when car is running.

You don't need an amp between tablet and harness, car wants a line level signal. Get the 'headphone' volume set right and it should work fine. Split the wires and connect them to A8-11 and B8-11 as you planned. If you have EQ controls over the tablet output you can probably get it sounding pretty good.

 

agreed 100%

 

Thank you for the quick reply.

It looks like I will end up going the C2R-GM24 route, wiring into the fuse box always seemed, for lack of a better word, tacky. The Bybyte amp was one of the first items I ordered and is well past their return policy. If they will not take it back, would wiring it into the system increase the volume level (in the event that I want the car 2 lengths in front of me while on the highway to hear me blasting the Conan the Barbarian soundtrack)?

 

If you're keeping the oem amp/speakers the new HU/tablet won't be any louder than what you have now. You can try it, but the increased voltage will just make the music distort, probably even at a lower volume than now.

My initial install would be without the amp. If volume is noticeably lower than stock radio then try the amp, but I'm guessing you'll have the tablet volume at less than full for best sound.

 

Thanks again Mark. After reading through too many post here to count, your knowledge of electronics is superlative.

In a parked car in the garage, the max volume is not uncomfortable, but it seems loud enough. I am not sure if it will hold up to 70 mph with the top off and windows down though. At this point, the cost and work to wire up the Bybyte amp has been a put-off, just to see what it would sound like. From the other thread, I got the impression that maybe a line driver would do a better job if I needed more volume.

One more question. My assessment from the layout was that the B3 blue wire was just a lead wire (on/off switch) and the amp had its own dedicated power source. Is this correct?


Sorry for the late reply, I work rather slowly on these DIY projects.

 

you are correct about b3 and a line driver would do the same in this instance

 

Great. Thanks

 

what will i need to make the CR2 work? A male 3.5mm to rca then something like a RCA Male to Dual RCA Female Adapter to turn the 2 rca's into 4?

 

That would do it