QuestionI was installing a head unit in my 2001 celica and I bought the wire harness and it does not match the one in the car. The on I bought has 2 smaller plugs and I only have one large plug that is attached to the car. Is there a different wire kit that I need or do I just splice into the factory wires and hook up the head unit? if so then I need the wire schematics for the stock wires. thanks for your time
AnswerHi,
The problem is that your Celica is equipped with a factory amplifier. Vehicles with amplifiers have a single plug at the stock head unit, and the head unit output is low-level with a common signal ground. This isn't compatible with the after-market deck's speaker outputs, although you can integrate the factory amp using the RCA outputs.
You have two choices: you can integrate the stock amplifier, or bypass it. Bypassing the amp means connecting the stock speakers directly to the new head unit's speaker outputs; integrating the amp means that the new head unit just feeds a low-level signal to the amplifier, so that it works similarly to the factory deck and the stock amplifier continues to drive all the speakers.
If you're keeping the factory speakers in the car, then I'd recommend integrating the amplifier. This is also the easier option for installation. To integrate the amplifier, you need a different adapter: Metra's 70-8113 harness. This should fit the single factory plug; it's designed to connect to your after-market deck's RCA outputs, rather than the speaker wires. To use this harness effectively, you'd need a head unit that has separate front and rear RCA outputs.
If you're upgrading the speakers, then bypassing the amplifier may be a better idea. This involves locating the speaker wires at the factory amp location to the right of the glove box, unplugging the amp, and extending the speaker wires to the head unit location. If you decide to pursue this option, let me know and I can give you more detailed wiring information.
Hope this helps!
Brian
