Cant get sound out of stock speakers with aftermarket stereo do i have to bypass factory amp

It is usually better to buy a direct replacement from a breakers yard.

https://www.google.com/search?q=2007+Kia+Sorento.+How+do+I+bypass+the+factory+amp

yes, you must bypass the stock amp. kindly follow the video link below as it will guide you on what to do and how to do it. In this video we take you through the steps to bypass a factory amplifier when replacing your cars radio.

https://youtu.be/SQQzykxcMUo

Might be able to get an adaptor that plugs straight in painlessly.
Failing that it's the standard trace and identify method that eats time like crazy.

You should be using line out from your aftermarket stereo if using the vehicle's existing amp. Then again, you may choose to bypass it, depending on the power being put out by your new stereo.
In both the Expedition and Excursion, the sound systems are different than smaller Fords. The Eddie Bauer typically had the Premium sound system, and the wiring can get tricky with those. You want to make sure it's done right so you don't short out and damage the amp circuit in your new stereo.
If all you're using is the existing speakers, then go ahead and bypass.

If you bought a wiring adapter kit for the aftermarket stereo, the unit should hook up directly to the stock bose system. Note: If there is sound coming from the speakers after installation, the amp IS hooked up...the speaker wiring is routed to the factory amplifier, not the stereo itself, the stereo wiring is just signal leads to the amplifier. In some instances, you may have to connect the amp remote wire to the remote wire coming from the aftermarket stereo(blue wire). I hope this helps. Any other questions, just reply.

These cars have a factory amp system that will not operate correctly with an aftermarket stereo. You have two choices. You can either run new wires to the speakers your self which would bypass the factory amp. Or you can order the premium sound system Interface here http://www.myinstallkit.com/FORD/1990%20(90)%20FORD%20THUNDERBIRD%20Radio%20-%20Stereo%20Installation%20Kit.htm scroll about half way down the page.

I had the same problem when I changed out the factory cd player. I finally found the problem was that grand am gt cars have a couple of amplifiers with crossovers in them for the speakers and the after market stereos put out sound that has been slightly amplified already and when you hook up your new stereo to the wiring harness your sending amplified sound from your stereo the the factory amp then to the speakers this sometimes messes with he sound and clarity of the sound. My car is 2002 and the factory amps are located 1 under the glove box and 2 in the trunk behind the carpet on the drivers side. The amp and crossover in the front is to split the signal for the door speaker and the tweeter by the mirror and the amp in the trunk is to split the signal for the two way speaker in the back by the back window witch if they are like my factory speakers have 2 wiring harnesses connected to each speaker. the only way I could get mine to sound good was to run new wires from your stereo directly to the speakers and bypass the factory amps. This may not be the only way to fix this issue but it was the only way I could figure it out. I hope this helps

You need to:

Wire the low level output from the new 'deck' into the stock amp input.

Or replace the stock amp with an aftermarket amp.

The amp is under the driver's seat, but you can bypass it using a wiring kit from any local car audio place. It is an installation kit for any aftermarket stereo and should include instructions on how to use the kit with or without the factory amp.

Here it is.

1996 Ford Explorer Car Stereo Radio Wiring Diagram
Car Radio Constant 12v+ Wire: Green/Violet
Car Radio Switched 12v+ Wire: Yellow/Black
Car Radio Ground Wire: Black/Light Green
Car Radio Illumination Wire: Light Blue/Red
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger: Orange/Blue
Car Stereo Amp Trigger Wire: Blue (If Equipped)
Car Stereo Amplifier Location: N/A
Front Speakers Size: N/A
Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Orange/Light Green
Left Front Speaker Negative Wire (-): Light Blue/White
Right Front Speaker Positive Wire (+): White/Light Green
Right Front Speaker Negative Wire (-): Dark Green/Orange
Rear Speakers Size: N/A
Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Gray/Light Blue
Left Rear Speaker Negative Wire (-): Tan/Yellow
Right Rear Speaker Positive Wire (+): Orange/Red
Right Rear Speaker Negative Wire (-): Brown/Pink
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