The left side speakers go in and out, the right side work fine, I am wondering if it is a wireing problem or a fuse

The Amp in the trunk might have blown,
Town Car Radio Wire Diagram
Car Radio Battery Constant 12v+ Wire: Pink/Light Blue
Car Radio Accessory Switched 12v+ Wire: Yellow/Black
Car Radio Ground Wire: Black/Light Green
Car Radio Illumination Wire: Light Blue/Red
Car Stereo Dimmer Wire: Blue/Red
Car Stereo Antenna Trigger Wire: Blue
Car Stereo Amplifier Location: Trunk
Car Audio Front Speakers Size: 5? x 7? Speakers
Car Audio Front Speakers Location: Doors
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
Car Audio Rear Speakers Size: 6? x 9? Speakers[img src="http://www.assoc-amazon.com/e/ir?t=modilife-20&l=as2&o=1&a=B00009UHRE" width="1" height="1" border="0" alt="">
Car Audio Rear Speakers Location: Rear Deck
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
Check the fuses

check your wiring

IF THE AMP DOESNT HAVE ONE THAT MEANS THAT THE AMP IS NOT WIRED RIGHT OR THAT THE AMP IS BAD

Here is a list of radio wiring harness wire color codes and what they do. I have given both with and W/O Bose.

Nissan Maxima Car Stereo Radio Wiring Diagram Radio Constant 12V+ Wire: Pink/Blue
Radio Ignition Switched 12V+ Wire: Blue/Black
Radio Ground Wire: Vehicle Chassis
Radio Illumination Wire: Red/Blue
Radio Dimmer Wire: Red/Orange
Radio Antenna Trigger Wire: Black/Red
Front Speakers Location: Doors
Left Front Speaker Wire (+): Blue/White
Left Front Speaker Wire (-): Blue/Yellow
Right Front Speaker Wire (+): Brown
Right Front Speaker Wire (-): Brown/White
Rear Speakers Location: Rear Deck
Left Rear Speaker Wire (+): Red
Left Rear Speaker Wire (-): Green
Right Rear Speaker Wire (+): Blue
Right Rear Speaker Wire (-): Pink
1997 Nissan Maxima with Bose Stereo Wiring Diagram W/Bose
Car Radio Battery Constant 12v+ Wire: Pink/Blue
Car Radio Accessory Switched 12v+ Wire: Blue
Car Radio Ground Wire: Chassis
Car Radio Illumination Wire: Red/Blue
Car Stereo Dimmer Wire: Red/Yellow
Car Stereo Antenna Trigger Wire: Black/Red
Car Stereo Amp Trigger Wire: Green/White
Car Stereo Amplifier Location: Each speaker has its own amplifier located at each speaker.
Left Front Speaker Positive Wire (+): Yellow
Left Front Speaker Negative Wire (-): Brown
Right Front Speaker Positive Wire (+): Violet
Right Front Speaker Negative Wire (-): Light Green
Left Rear Speaker Positive Wire (+): Red
Left Rear Speaker Negative Wire (-): Green
Right Rear Speaker Positive Wire (+): Pink
Right Rear Speaker Negative Wire (-): Blue

Check the fuses. The left and right sides have seperate fuses for the lights. Not sure about the speaker, that might just be a coincidence that it doesnt work. I reacently worked on a hyundai that had the same problem.

Hi, there is a factory wire (red with a black stripe) in your car for illuminating the stock radio. This wire is not to be used in an aftermarket radio, so you need to make sure it isn't connected and also isolate and bare wire with electrical tape. Please let me know if you have questions, and thanks for using FixYa.

1999 Mazda Protege Car Stereo Wiring Diagram
Car Radio Battery Constant 12v+ Wire: Blue/Red
Car Radio Accessory Switched 12v+ Wire: Blue/Black
Car Radio Ground Wire: Black/Yellow
Car Radio Illumination Wire: Red/Black
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 6 1/2? Speakers
Car Audio Front Speakers Location: Doors
Left Front Speaker Positive Wire (+): Violet
Left Front Speaker Negative Wire (-): Blue/Orange
Right Front Speaker Positive Wire (+): Yellow/Blue
Right Front Speaker Negative Wire (-): Violet/White
Car Audio Rear Speakers Size: 6? x 9? Speakers
Car Audio Rear Speakers Location: Rear Deck
Left Rear Speaker Positive Wire (+): Yellow
Left Rear Speaker Negative Wire (-): Orange
Right Rear Speaker Positive Wire (+): Green/Orange
Right Rear Speaker Negative Wire (-): Green/Black

:o( you're going to have to pull the radio out to see what they did. They probably added a wire to an inappropriate circuit to power the new radio or amp. I will paste your factory wiring colors below. If you now have an extra wire, that is the likely culprit. Trace it to see where they hooked it in. If it isn't going to the the fuse box and using an extra slot, make it so by connecting it to the cold side of the fuse and put an approprite size fuse in. To determine the fuse size to use, you can compare the wire gage to other cold side wires and use a fuse the same size as you see being used for similar gage wires. Let me know if you have more questions.

1996 BMW Z3 Car Stereo Installation Diagram
Car Radio Battery Constant 12v+ Wire: Red/White
Car Radio Accessory Switched 12v+ Wire: Violet/White
Car Radio Ground Wire: Brown
Car Radio Illumination Wire: Gray/Red
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: White
Car Stereo Amp Trigger Wire: White
Car Stereo Amplifier Location: Passenger Kick Panel
Car Audio Front Speakers Size: N/A
Car Audio Front Speakers Location: N/A
Left Front Speaker Positive Wire (+): Yellow/Red
Left Front Speaker Negative Wire (-): Yellow/Brown
Right Front Speaker Positive Wire (+): Brown/Black
Right Front Speaker Negative Wire (-): Blue/Brown
Car Audio Rear Speakers Size: N/A
Car Audio Rear Speakers Location: N/A
Left Rear Speaker Positive Wire (+): Blue/Black
Left Rear Speaker Negative Wire (-): Yellow/Brown
Right Rear Speaker Positive Wire (+): Blue/Violet
Right Rear Speaker Negative Wire (-): Blue/Brown

Check the ground connections for the speakers.

here is the radio's wire color diagram, u should be able to fix the problem with this info.Fuse box is on drivers side under the dash.
1991 Ford Tempo Car Radio Wiring Guide
Car Radio Battery Constant 12v+ Wire: Green/Yellow
Car Radio Accessory Switched 12v+ Wire: Yellow/Black
Car Radio Ground Wire: Red or Black
Car Radio Illumination Wire: N/A
Car Stereo Dimmer Wire: N/A
Car Stereo Antenna Trigger Wire: N/A
Car Stereo Amp Trigger Wire: N/A
Car Stereo Amplifier Location: N/A
Car Audio Front Speakers Size: 6 1/2′
Car Audio Front Speakers Location: Doors
Left Front Speaker Positive Wire (+): Orange/Green
Left Front Speaker Negative Wire (-): Black/White
Right Front Speaker Positive Wire (+): White/Green
Right Front Speaker Negative Wire (-): Black/White
Car Audio Rear Speakers Size: 5′ x 7′
Car Audio Rear Speakers Location: Rear Deck
Left Rear Speaker Positive Wire (+): Pink/Green
Left Rear Speaker Negative Wire (-): Pink/Blue
Right Rear Speaker Positive Wire (+): Pink/Blue
Right Rear Speaker Negative Wire (-): Green/Orange

Here is the radio wiring color's and what they do, all have the harness installed.

Car Radio Constant 12V+ Wire: Light Green
Car Radio Switched 12V+ Wire: Yellow/Black
Car Radio Ground Wire: Black
Car Radio Illumination Wire: Light Blue/Red
Car Radio Dimmer Wire: N/A
Car Radio Antenna Trigger N/A
Car Radio Amp Trigger Wire: Blue
Front Speakers Size: 6 1/2′
Front Speakers Location: Doors
Left Front Speaker Wire (+): Orange/Light Green
Left Front Speaker Wire (-): Light Blue/White
Right Front Speaker Wire (+): Dark Green/Orange
Right Front Speaker Wire (-): White/Light Green
Rear Speakers Size: 5′ x 7′
Rear Speakers Location: Side Panels
Left Rear Speaker Wire (+): Gray/Light Blue
Left Rear Speaker Wire (-): Tan/Yellow
Right Rear Speaker Wire (+): Orange/Red
Right Rear Speaker Wire (-): Brown/Pink
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