OK - I received my Pioneer head unit the other day and I want to try to install it this weekend. I removed the old HU already and am laying out the wires to make sure I know where everything goes. I bought the Metra harness recommended by Crutchfield for my car and the HU I bought. Tonight I did a temporary hook up of the major wires I thought would be required to operate and hopefully correctly, however I got nothing, not even a hint of life in the HU.

Therefore I have marked up a couple diagrams and I hope I can get some of you guys that have done this already to check my logic and see if I am headed in the right direction. I have notated both diagrams with how I connected each of the wires. Please check my work and see if I'm sane or not.

Also - what kind of brackets should I use to physically mount the head unit in the hole. It will easily slide all the way back without any modification. They must be getting smaller.

Thanks for your time.

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Violet/white wire is for your back up function. Splice it into either the backup lights or if the trans has a backup switch that is closer.

The yellow/black is for a mute function for aftermarket items, cell phone, etc, that will automatically mute the radio when it senses power to the item. It is useless to you, there should already be a manual mute function on the remote.

For the parking brake relay issue, that is so you can't watch movies while driving. There is a bypass instruction on the internet somewhere, you should be able to find it.

As far as the antenna and dimmer functions, the color codes are below:


1994 Chevrolet Corvette Car Stereo Wiring Color Codes

Car Radio Battery Constant 12v+ Wire: Orange
Car Radio Accessory Switched 12v+ Wire: Yellow
Car Radio Ground Wire: Black
Car Radio Illumination Wire: Gray
Car Stereo Dimmer Wire: Gray/Black
Car Stereo Antenna Trigger Wire: Pink
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 4″
Car Audio Front Speakers Location: Kick Panels
Left Front Speaker Positive Wire (+): Tan
Left Front Speaker Negative Wire (-): Gray
Right Front Speaker Positive Wire (+): Light Green
Right Front Speaker Negative Wire (-): Dark Green
Car Audio Rear Speakers Size: 6″
Car Audio Rear Speakers Location: Rear Sides
Left Rear Speaker Positive Wire (+): Brown
Left Rear Speaker Negative Wire (-): Yellow
Right Rear Speaker Positive Wire (+): Dark Blue
Right Rear Speaker Negative Wire (-): Light Blue

Good luck,

Matthew

As far as the brackets, you should be able to remove the ones from your stock head unit and use those. Otherwise I've used L-brackets and a/c hangers in the past.

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I got this one taken care of. Using the relay for that.


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These wires are in the two connectors that went into the old head unit? I thought the whole idea of the $49 Metra Cable was so I didn't have to splice into the factory harness. Oh well that's ok.

My old HU had no brackets, just metal tabs that were bent off of the chassis - I will go to the store and buy some metal straps and make some "L" brackets.

OH and thanks a bunch Matt!

Thanks Matt, lots of good information there.

1. Where is the best place to connect to ground for Head Unit?

2. Do I have to do anything with the speaker leads from the new Head Unit if I have plugged in the RCA plugs to the rear of the new Head Unit. (I think not, but just asking)

3. The color coded wires that Matt listed are they located in the dash harness or inside the rear compartment with the old receiver?

Well, I talked to the techs at Crutchfield and got some more information about the Metra bypass cable. I hooked everything up like they said and I still have nothing.

This is frustrating.... I'll keep on plugging on, but I must have something miswired somewhere, I'm not getting anything from the head unit at all.

I am sorry about that, Don. I'm more of a hands on guy so I wish I were closer.

Did you verify your power to the head unit with a DVOM? If the HU is not turning on, you don't have power/ground. Not to be insulting, but did you make sure you turned the HU on once the car was on? On pioneers, you can turn the unit 100% off and there will be nothing showing on the screen.

As far as the ground location, there should be several places in the dash there. I think I used an anchor point along the trans tunnel.

For the speaker leads vs RCAs, depends on which RCAs. That is a high end unit and should have RCA outputs for both front/rear high (speakers) and subwoofers. Make sure you have the right ones plugged in. The speaker wires from the HU are unnecessary at that point.

I don't know where specifically the colored wires would be, sorry.

Matthew

Thanks again Matt. Yup to all of the above.
Crazy - since I used to build radar systems for F-16 but I can't get this damn radio to work.

I can't get 12 volts from the harness in the back. It must have been hot before as the Bose HU was getting juice.

Can I apply 12 volts directly to the HU while grounded to test the unit?

Thanks Matt - I'm sure I'm missing something simple and will figure it out.

hm... thinking...

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More than likely there is a turn on lead for the power source. IE, an amp wire or antenna wire that goes from the head unit to the controller. Once it senses a signal it will draw power.

Matthew

Let's first review how the 90-96 stereo works, then address what may be going on here.

The 90-96 system has a head unit, a brain box (reciever module) and then the speakers.

It really doesn't matter if it is Bose or Delco, the architecture is the same.

Where it differs is the power source for the speakers. If you have Delco, the power is in the brain box, in the Bose, the power is at the speakers.

What the Bose does, tho, is require a line level signal. The question that I have never been fully clear on is what kind of line level signal. For years, ppl have bought these adaptors to use aftermarket heads with Bose... but those are usually noise factories.

Apparently, this cable is some kind of bridge to the reciever brain box and allow the new pioneer head to fire it up. That unit MUST be powered or the speakers won't work - at the same time, the speaker relay that must fire or else the speakers won't work.

If the wiring is correct, I don't see why it won't work... Or more accurately, function. It might work - i.e., make music, but I am curious if the music will sound all that great...

I think I am seeing the problem.

If you unplugged the brain box, it won't be able to fire the relay. Judging from what I have read, if I got all the details correctly, you unplugged the brain box. From what I am seeing here, the brain box should be getting fed a signal from the line level outs from the Pioneer head and then into the bose box to the speakers.

Either that, or this harness is supposed to bypass the Bose brain...

There are harness plugs on the back of the Delco head unit. I am wondering if the interface cable shouldn't plug into that and feed into the brain, versus bypassing the brain.

Just a few thoughts... I find the instructions included with the harness to be vague, at best.

Thanks for the comments Andy

I think the intent of the harness is to bypass.

As far as the connectors at the head unit under the dash, there are two, but they will not fit the adapter harness at all.

Tomorrow I'm going to take some copies from my FSM out in the garage and map out each connector and try to figure out what is going on. Now, I know why everyone says the Bose system is so complicated. What the heck were they thinking?

I really hate to give up and take this thing down to Best Buy for installation!!!

Don't take this to Best Buy.

This is exactly why I suggest doing a fresh install. Lose the bose completely. Speakers, amps, do it right or don't mess with it.

I have heard a number of these systems done with adaptors and such, and they all suck for SQ. They are no better than bose OEM SQ and if anything, worse.

The bose system uses rather shitty drivers in an enclosure that essentially tortures the air to get the response they think the ear should hear.

I would feel better about bose if they used quality hardware to do this, but they don't. They use cheap paper cones (not that paper is bad, I prefer it for SQ, but I prefer a heavier weight with a coating for all weather protection) and nominal quality electronics for the amps.

The system uses a small 50 watt amp. This amp is 1 ohm stable. Meaning, an amp the size of a cigarette pack will do the work of a much larger amp. Normally, car stereo amps are 4 ohms. At the size of these amps, 4 ohms would produce a messy 12.5 watts. As it is, being 1 ohm stable, these amps are pushing a really ugly 50 watts.

The front has a 5" driver and a 1.5" driver. 1.5" is just too big to be a tweeter, and that's what they are asking it to do. In the rear is a 6" driver that does nothing much more than mid-bass and some sub-bass.

Later C5 systems use a bigger amp, but equally crappy speakers.

The C6 system is marginally better, but not by much.

What really fumes me is that Bose CAN build a fairly good system if they want to. They do the Ferrari, Mercedes and Maybach systems. They still lack bass, but the highs and mids are much better.

Bang and Olafson does the best car audio system, period. The Mark Levinson used in the older Lexus were actually pretty good.

The latest Rolls Royce uses a Lexicon based system with like 22 speakers! There is this array in the rear that flat out bumps, yo. Impressive. I had the opportunity to listen to one at the LA Concours a couple years back. Wow. I guess when you unass that kinda money, you get something special, but this was exceptional. Very well thought out.

Did you ever hook up the antenna wire? I'm thinking that might be related.

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I did, and still nothing.

Today I'm going to try a fresh approach and if I have no success, I'll go the route Andy has preached all along. I actually planned on doing the whole system, speakers, amp and sub anyway, but thought perhaps it might be ok to do it in steps and see what the factory speakers sounded like behind this HU first.

I'll keep you guys apprised of my progress

Well first off I hate working on wiring in cramped quarters

Next: Murphy's Law of auto wiring. "Anywhere there are bare wires they will surely find one another and cause sparks!!"

I couldn't get a hot 12 volt because apparently I blew a fuse on the RDO BATT line. I finally decided to check fuses after beating my head on the dash wondering why I couldn't find juice. However that's not totally solved my problem yet because I still couldn't get power to Head Unit from the Metra Adapter Cable. The Cable does work wonderfully linking the speaker amps though.

The only way so far I have been able to get the HU to fire up and work, is to attach both the yellow constant pwr lead and the red switched power leads from the HU to a constant 12volt source and it works great.
Only problem is that the HU will never turn off this way.
I'll figure that one out tomorrow.

As far as sound quality... I swear, cross my heart, because I have no reason to BS you guys, that this HU sounds great with the Bose speakers! Plus, I still can add a Sub later as the HU has RCA inputs for a subwoofer too. I played music off a USB thumb drive, SD card and my DROID as AUX IN and it sounds great. It will drive louder than my old Bose HU for sure. I don't know how this is, but I swear its sounds sweet. I was grinning from ear to ear when I cranked it up and got no distortion or crackle.

I am experiencing a pop when I exit the radio source and the antenna lowers. I wired in a switch for the antenna years ago and probably will just leave it down as I always have.

I'd show photos but at this point its just a mess of wires EVERYWHERE inside the car. This week I will iron out the little problems and figure out how to hide all of this wiring.

Thanks to Matt and Andy for prodding me along. You suggestions help to think things through.

Good work Don. Feels good to get ten steps ahead after taking so many back. Looking forward to some pics when it's all done.

I am shocked it will play louder... I know that SQ has a lot to do with line level quality, but those amps are real limiting factors.

However, I am glad you are happy!!!!

I got an AI Net interface for my Alpine that allows me to play the Zune through my older 7998. It's been neat... It creates RCA aux inputs... two of them... technically, I could run a turntable off the car stereo...

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I never could get much volume out of the old system. It had to be something wrong with the old Bose HU. I could never get any volume until the knob was at the 2 or 3 o'clock position and often when cranking the volume to a good tune would just crank the volume full right, wanting more! Maybe I just got wax in my ears!

I hope to get this cadaver sewed up this week.

Glad you found the problem!

I never even thought to check the fuse, I disconnect the battery before doing most electrical/stereo work.

Matthew

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I figured someone would jump on that! He He

I had to have the BAT connected to test my connections and well... See Murphy's law above

Whenever I work on car audio, I never disconnect the battery. You need power to test this crap, so why disconnect?

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So you don't accidentally blow a fuse and try tracking it down for 5 hours

I have this uncanny ability to hear them pop.

OK, speaking of things going Pop!

I finally got it working. Turns on and off with the ignition etc. Sounds awesome, I'm happy...

But....

What causes the Pop when I turn the HU on our off! The volume can be set on zero but it will still make a pretty loud Pop! out of the speakers when it first powers up or down. Its annoying and it can't be good for something.
Any ideas?

That's the speakers cycling... sorry... most aftermarket amps have built in circuits for soft shutdowns - ie, no pop.

I am not sure how you are gonna beat that one out...

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The amps/speakers in the door turning off. You will get rid of that if you get rid of the door amps.

I just got off the phone with this guy...

Dave Navone

He says that there are ways to remove that pop by using relays to delay the time that the amps get signal but it would require one for each channel.

He also said that if I can live with the Pop it aint hurting anything. So... I'll see if I can live with the pop and save my nickles to get some new speakers, amps and sub.

Now I have to mount this HU and button it up and I'll be good to go for now.

Another learning experience with the Corvette!
Isn't it great!

Lets see some pics of the final install.

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I'm hoping to have everything mounted this week, but I'm just sending off my shift plate, radio bezel, and ac outlet covers to be finished in carbon fiber.

So... the whole thing still won't be done for another month.

But I will post photos shortly

Since there are a few audio threads going. I thought I'd ad a quick photo of the HU sitting in place and powered up!

I'm getting close to being able to button it all back up, but I'm waiting to buy the XM receiver and get my shift plate and radio bezel back from the finisher.

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nice! Very nice!

Screen looks very clear! Nice job.

Matthew

What color the carbon fiber? Don't they make kits like for the C5's amd 6's?