gcinfl

I got tired of having my car torn apart. I felt like I had violated her. I'm want to drive my car tomorrow and see how many squeaks and rattles I installed, so I put her back together.

I could NOT find any amp under or behind the glovebox. If somoene can find an amp behind the glovebox, I want to see pictures. Z461, are you sure your installers found an amp behind the glovebox? I think there is only the one amp under the styrofoam in the left rear deck between the spare tire and antenna.

My Bose hunt is over for awhile. Someone else can take over now.

Questions for Z461 to ask his installers:

1. Were there one or two amps? If two, exactly where is the one behind the glovebox?

2. What signals did they find on what wires (color codes)? Did they find all the signals they needed in the bundle going to the rear amp? I think you said they did, but I just wanted to confirm. Please confirm the signal levels also.

3. Did they remove, power-down, and/or disconnect the Bose amp entirely? I assume so. I want to make sure the head unit still works without the Bose amp connected to it. It appeared to work when I disconnected them, except for no sound from speakers, which is to be expected, unless you think some of the speakesr are powered by the head unit.

4. Which amp(s) drive each of the 7 speakers? Does the head unit drive the tweeters as mentioned?

I believe that there is only one amp in the back and that all 7 speakers may be powered out of it. I'm skeptical about the tweeters being powered by the head unit because when I disconnected the Bose amp, those tweeters didn't make a peep.

My best guess is that what Z461's installers did was to use the DVM visible in the photo to find the four line-level signals. Using the balance and fader control and a DVM, you should be able to identify the four wires you want out of the 20 in the bundle. Then they probably just ran those four line-levels into their aftermarket amp and ran new wires to all the speakers. I don't think the stock wires could handle the power of the aftermarket amp and speakers.

I would think that anyone thinking about putting in an aftermarket amp and replacing the Bose could follow this procedure. It would be nice if someone who's done it would just post the color codes of the four wires we want and confirm their existence and signal levels. They might be speaker-level outputs. If so, it appears that most 5-channel amps available now have both line and speaker level inputs.

It would also be nice if someone could get a peek at a technical service manual on the Bose system so we could come up with a way to defeat the auto-EQ/VOL function until we replace it. I would probably just live with it, myself. But the subwoofer would still sound like it was wrapped in a blanket and stuffed in the gas tank.

gcinfl

I swear I went on eBay last night and started looking for a scope, just for this purpose. Scoping out those wires would be fun. A DVM might suffice just for finding the speaker I/O, but to try and figure out which signal might be the input or control for the dynamic EQ/VOL will really require a scope.

As far as the disconnect, I did both. The speakers went dead, but not the head unit, when I pulled either or both of the two connectors. Not surprising. I think one has the power and the other has ALL the speakers.

I would already have a new amp in there if I had thought the factory speaker wires were heavy enough. I don't want to do all the disassembly that is required to run new speaker wires to all the speakers (probably wouldn't have to do the tweeters).

The good thing about the styrofoam is that it will be easy to cut out around a larger amp. The way the amp is mounted is upside down with the heat sinks facing downward about 1" off the floor below it. There is a sheet metal bracket holding it upside down off the floor that screws down with 3 screws. The amp is screwed to the bracket with 4 screws.

With a scope I think you could pull the cover off the amp (looks like just 2 screws) and trace signals around the circuit board.

To get to the amp:

1. Pull out rear deck carpet, mat, fiberboard, spare.

2. Remove felt piece on left rear quarter-panel inside by pulling off the plastic piece that slips under the hatch door seal (pull up).

3. Pull off plastic piece on rear inside that contains the hatch area light.

4. Now the fun part is maneuvering the styrofoam out from under the strut tower brace left side base and up. You can't just slide it sideways, that's why steps 2-3 are required.

You're there. Happy signal hunting.

Take a look at the wire gauge to the speakers, if that's where they go, so we can calculate how much power they can handle. I'd really like to swap out the amp if it can be determined it can be done without replacing the wires. The other problem is the power to the amp. I don't think those wires are heavy enough either. Let me know what you think.

I'm thinking of just a little 5-channel amp to replace the Bose. It's hard to find one that's less than about 350W total (4x50, 1X150).