matthewkleinmannGetting the stock radio out was easy. I am not a total stranger to doing car audio installs so I figured this was a piece of cake. As it turns out not all cake is sweet nor easy to swallow. Think stale carob. I used to have a girlfriend who ate that um, substance, but I digress.
The good news is that the harness behind the stereo was not all hacked to hell, in fact it was pretty much intact. Interesting news was the stock radio that came with it was from a junkyard as it had the junkyard markings on it Also of note the heavy orange wire that goes to the unswitched 12V line on the harness was cut and spliced right next to the connector to the radio. Why someone would hack it there... And there was a random red wire coming up from under the bowels of the dash that was snipped off and just sitting there. Hmmmm.
I have a long drive and I really want tunes and I have my tunes and books on tape for this trip on a USB stick already, and the aftermarket stereo has a slot for USB sticks. This is good. The stereo also came with both a plug that fir the wiring on the back of it, and a plug that fit into the radio plug on the harness. I need to mention that at this point in time I was working in the parking lot of the fleabag motel I was staying at, so this was going to be a quick splice and tape job, until I got to my much more technical friends place and I could fix it properly.
Everything lined up great, except for two little issues. One was no power and the other was no sound. It looked cool though, so it gets a major plus for that. I managed to get it full time power by using that spliced into unswitched orange wire to go into the switched red wire. Not ideal, but I figured I could live with it until I got to more civilized surroundings. However, as is often the case in my life, nothing can ever be easy, even though I had power, I had no sound. Great.
Not being one to give up too easily, I recalled that I had a pair of headphones in my computer bag. Nasty cheap $1 store phones but audio transducers none the less. As soon as I got one channel of the stereos speaker output across the 3.5mm jack on the phones (not entirely easy to do by ones self BTW) I ogt good FM hiss, and when I got the coordination down to hit the seek button while holding said jack, I was greeted with actual music. Not my kind of music but enough to tell me that the aftermarket stereo, or at least that channel of it, was happy.
I ran out of time at that location, so I got to do the 2 hour drive to my friends place sans any audio. It was also pouring out and I am not used to 3 lanes of traffic going near 80 mph. Just when I thought this was really starting to suck, my phone, which was my navigation too a dump on me. My charging set up at home is a transformer that has a permanently attached microusb cable. I figured for the trip it might be more versatile to grab another transformer that ends in a regular usb connector and a regular usb to a micro usb. I also grabbed a 12Vto 120V inverter that plugs into the cig lighter for my notebook and a cig lighter to usb for the phone, and of course a usb to micro usb cable. Sadly I did not thoroughly check out the cable. The good news is it can charge my phone. The bad news is it needs to be in the exact correct position to do it, and barreling down the road at 75mph is apparently not in congress with being in the correct position.
Before I left one of my friends printed me out google maps directions to here. So I pulled over and attempted to look at them. I could not figure out the lights with out the door open and it was pouring, and the person who printed out the "directions" skipped the text part and printed out a map about the size of a passage stamp and in black and white. Can you say totally useless? I also did not wanna stay roadside too long. The guy I bought the car from told me with the paperwork I had 30 days to register it, but coming from the east I find it hard to fathom they will just let you drive around for 30 days with a title signed over to you and a cash receipt and nothing else. No plates..
The good news is I have been here before and I have a decent memory. I recalled one exit that I knew I had taken before and almost tried it, but I was saved by Colonel Sanders of all people! No shit. I recalled that I remembered that exit because that town has the elusive all you can eat KFC in it. If you love KFC, it is a pilgrimage you should try at least once in your life. I find it best to go in with something bland in your tummy to start with and than start piling on the grease. Umm. I have a real weakness for KFC. Anyway, the Colonel saved me from that exit. Three exits later I thought I had the right town, and sure enough I did, but I had to make a right-left choice so I trusted my gut. About 10 miles down the road I saw stuff that looked familiar. Yahoo. The last hour and 45 and bunch of turns were on autopilot. But the closer I came the more I recognized and the more backwoods it got. I live in the backwoods so the crazy windy mountain road was much more peaceful to me than the nasty 3 lane traffic (which admittedly had subsided down to nasty 2 lane traffic by the time I got off...) Anyway I got here.
That night I thought about it and figured either I have the worst luck of all time and all of the speakers are dead or the car has an amp. Don't laugh about all 4 speakers being dead, in my truck 2 of them were when I got it. Anyway, after tons of web searching I verified that I have the advanced pioneer system with rear controls and an amp. It also has a lot of speakers. At least 3 sets and one set of unbound tweeters. Put and asterisk after that.
The good news is I was able to find the amp with some help from the net. The bad news is no one seemed to have the pin out. Great. So we start. As luck would have it I had rewired some ballasts for my friend here to illuminate his uranium glass collection and the old ballasts had nice stiff solid conductor wire coming out of them. Oh and my friend gifted me a neat-o dvm in a probe. So, I went through the speaker wires on the radio side and ohmed them out on the amp connector I drew a picture of how I held the connector and numbered the radio 1 to 24 for the pins and used letters for the amp side. So now I knew where all the radio out wires were on the amp connector. I gave my sore back a break for the rest of the day and the next day went out with a AAA cell and some stiff wire and started probing until I got static in a speaker. The speakers are kind of logically laid out in the connector so once you get with it they are easy to find. Yahoo.
I spent a day fretting the phasing but in the end figured sound was better than no sound, and given we are a long ways from anything up here, I was going to have to make do with what I had. So back into the shop and I came out with a handful of stuff insulated wire jumpers and you guessed it, I jumpered the amp in pins to the speaker pins. With a wee bit of pushing and twisting all the speakers got static from my battery going into the harness. +1 so to speak.
Next AM, I took the radio and the harness in the house and did a nice job with solder and heat shrink and ran it back out. It turned out the mystery red wire was the switched +12V line so I got that fixed. Tunes! Yahoo.
Sorta. The biggest speakers seem to be in the back hatch area and the independent tweeters seem to be in the middle. I made a new set of jumpers that I may or may not deploy, these will let me parallel two speakers on one line. I also think my friend has some decent (large) value film caps that I can use for a tweeter crossover. The thought being to add the independent tweeters to the front and the back and hatch speakers together. Or something like that. At least until I get home.
While I was looking at this stuff, I also learned that I don't need to ditch my steering wheel and rear hatch controls. I have a Sony stereo and they have a very simple system for the remote in on the back. It involves switch different resistances across two of the pins. The remote controls in the car work similarly. Only of course, the resistances are different. I have already conceptually figured out what I need to make this work, just about any small micro controller with one analog input and a digital pot. Just for fun I worked out the numbers and it seems like it would be easy to use the o chip ADC to read the steering wheel buttons and than if they fall within certain ranges, send the appropriate value to the digital pot. I am not sure how fast the car stereo looks at the remote interface, but there is also a chance that something as simple as a 16 bit PWM channel driving on or a few CDS photocells in parallel might also be capable of doing the trick.
I say a few because they typically swing between a few hundred ohms in bright light to a few meghoms in the dark. A few of them in parallel would lower both of those numbers. As I recall CDS cells are not very linear so this would take a lot of trial and error playing with the PWM until it worked as well as it can. I am also not sure of thermal effects on CDS cells, that may make them unsuitable for this use.
BTW, on the radio, it gets better. It was not until I got the radio in the dash that I discovered that two of the buttons were missing. Shit. One is the power/mode button. On the plus side, I have a Sony in my truck and I had to get a remote for it, and the remote was under $7, so I ordered one. Even cooler is they ship them out of the Amazon warehouse in Ga so it was only a day to get here. Yahoo. That arrived the other day and the radio works great with the IR remote, and that duplicates almost all of the knobs on the thing.
And even cooler yet, is this radio comes with a truly stupid feature, you can adjust the RGB of the back light for the display. That was very annoying at first, but I soon discovered that I like it. I can dial the green and blue all the way down and dial the red down until the radio totally matches the other displays in the car dashboard. Too cool.
When I get home I can 3D print a filler panel or CD holder for the second half of the double DIN cutout. For the time being I am looking for a hunk of foam I can jam in there to keep things from ratteling around too much.
Next installment, when I feel like typing, I will go over my pinouts for the connectors and some links that I found and the resistance values for the buttons from the car and the values the Sony deck wants. I also found a link to some info on Autozone but it seems that I see the connector one way (as do a lot of other people oddly enough) but GM seems to see it another way. Urg. More later... Promise.
24 pin connector on radio 24 pin connector on amp Notes
2 7 Right Front drive from head
3 8 Right Front drive from head
4 10 Left Rear drive from head
5 9 Left Rear drive from head
14 11 Right Rear drive from head
15 12 Right Rear drive from head
16 6 Left Front drive from head
17 5 Left Front drive from head
1 Left front door speaker input
2 Left front door speaker input
3 Right front door speaker input
4 Right front door speaker input
13 Left rear door speaker input
14 Left rear door speaker input
15 Right rear door speaker input
16 Right rear door speaker input
17 Right Tweeter input?
18 Right Tweeter input?
19 Left Tweeter input?
20 Left Tweeter input?
21 Right hatchback speaker input
22 Right hatchback speaker input
23 Left hatchback speaker input
24 Left hatchback speaker input
Jumpers on 24 pin AMPLIFIER connector to connect speakers direct via radio harness
5 - 1 Left Front
6 - 2 Left Front
7 - 3 Right Front
8 - 4 Right Front
9 - 13 + 23 Left rear (door + hatch)
10 - 14 + 24 Left rear (door + hatch)
11 - 15 + 21 Right rear (door+ hatch)
12 - 16 + 22 Right rear (door+ hatch)
The pin numbers are with the side of connector with the little notch that is more on the inside of the connector facing upward, looking at the connector end (not the wire end) and counting from 1 in the top far left to 12 in the top far right and 13 in the bottom left and 24 in the bottom right. GM seems to label them differently. Also note that I could not tell the phase of the speakers so that may be wrong. For the right now trip, I just want sound!!
Dash and rear hatch resitive controller stuff......
Sony 3.5mm hardware jack on back of stereo resistance value for functions..
Function Ohms
Off 0
Source 2200
Mute 4400
Display 6600
Tuner up 8800
Tuner dn 12100
Vol up 16800
Vol dn 23600
Band 38400
I got the above numbers off the internet so take them with a grain of salt. I would hook up a 50K trimpot and verify (1) that the functions trip the correct order and (2) the "center" of where they trip is roughly the values here. Again, these are not my numbers.
Aztek Dash and hatch R values
Function Ohms
Vol up 1270
Vol dn 1564
Play 1948
Mute 2423
Seek up 3138
Seek dn 4318
AM/FM 6688
PRST 13668
These numbers come from Autozone's info on the Aztek steering wheel controller. Again I would hook an ohm meter to pins A6 and A7 (in GM connector nomenclature, not the same as everything above) and verify the values. If you have enough fingers you should be able to read the R values in the ladder by hitting all the buttons but the one you are interested in. That is hit everything but mute and you should read about 475 ohms.