Different factory-installed radios

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My wife's car is a 2005 Prius with AM/FM/CD, no cassette. She desperately wants cassette tape because of our library of books on tape. From what I have gathered, there are three factory radios for the 2004,2005 Prius.

Radio-A is AM/FM/CD only;
Radio-B is AM/FM/CD/TAPE;
Radio-C is AM/FM/TAPE/6CD-CHANGER(JBL).

Is it possible to drop in a Radio-C in place of the current Radio-A? Is the wiring/connectors the same? I know that the Radio-C JBL system adds an amplifier under the passenger seat, but what if you don't have the amplifier? Could Radio-C still power the speakers in a Radio-A setup?

Unfortunately, I do not have access to the factory service manuals to look up the connectors/wiring myself so I am hoping for community help. If I could get my hands on the few pages that show electrical wiring of Radio-A, I think that would answer my questions. I've found a car wiring/schematic diagram on the web for the Radio-C configuration but haven't found one for the Radio-A configuration Maybe somebody has a PDF of those Radio-A pages?

I have a Radio-C from one of the salvage yards and it's only the radio itself, without the under-seat amp. I bought it over the Internet last Thursday, not knowing about the JBL amp being seperate. I'd like to know if the C radio itself is acting as a pre-amp only (line out levels) or does it have a seperate set of outputs capable of driving speakers directly. There are a lot of connectors on the back of a Radio-C and I'm hoping that one connector, normally un-used, would provide some speaker-outputs directly from the radio; probably won't be the same power output/fidelity as the JBL amp, but usable. I am not a hi-fi maniac; I just want to be able to hear the sound and control the volume.

I figure that the dealer is called upon to upgrade/downgrade the radio from the factory when the customer wants a different radio than what the factory installed. They wouldn't send the car back to the factory to change out the radio. I can't see the mfr making it THAT hard to swap configurations.

Alternately, I am really interested in seeing any pix of the back of the Radio-A (AM/FM/CD non-JBL) that show the connectors. I ask this so that I don't have to tear-apart my dash twice, once just to see the connectors.

The Radio-C has a bunch of connectors and I am wondering if the Radio-C might also have speaker-drive capability (undocumented) for situations where there was no amp. Just a thought.

If anybody has the factory service manual that shows the connections to/from a Radio-A, I would really like to see them. Pictures of the back of Radio-A would also be great if somebody has them. It would save me tearing apart my dash for fact-finding if somebody has already done that. Thanks.

HELP!!!

 

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