Car stereo (radio) connectors and speaker wires identification

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BEFORE YOU START
This pictorial is a last of a series of pictorials about adding rear car door speakers in a vehicle.
You may wish to visit first:
DISCLAIMER:
Our pictorials are of informative nature and do illustrate works carried out by ourselves at our own premises for our own use and satisfaction.
Readers who envisage to carry out similar works inspired by the below method shall do this at their own risks and liability.

What's in a car stereo (car radio) connector:

You are seeking to identify the speakers output (wires) of an original car stereo unit out of many wires connecting to it.
Original in-dash car stereo units could have as a minimum the below listed wires in their connector:
Identification
No of wires
Function
POWER SUPPLY WIRES
Permanent positive
​
Switched positive
​
Ground
​
Positive OUT
1
​
1
​
1
​
1
Keeps the radio set powered in sleep mode (when the engine is turned off)
Powers up the car stereo unit when engine is running.
Provides a ground point to the car stereo unit.
Returns a + signal once the car radio set is turned ON.
SENSORS AND CONTROLS
External temperature sensor
​
Car radio ECU
2
​
2
Connects to the temperature sensor in the door mirror (through car chassis ECU).
Allows the car stereo set ECU to communicate on the CAN-BUS.
SPEAKERS
Each speaker on the right side
​
Each speaker on the left side
​
2
​
2
​
Such wires run up to the car speakers in doors. One is +, one is -.
Such wires run up to the car speakers in doors. One is +, one is -.

Identifying the car speakers wires - pictorial

Look within the thin wires (the thick ones being for the power supply) for pairs of wires of different color grouped together on one side of the car stereo connector or in a separate connector.
Note: each wire within a pair has a different color and wires between pairs have also different colors.

Set the multimeter at the AC voltage, highest mV or lowest V scale.
Use the test leads of your multimeter as shown on each pair to be tested.
No matter where you place the positive and negative lead terminals, just make sure they are touching the metal connectors.
Turn ON the car radio and watch the voltage which should increase with the volume (see below pictures).
If it is so, then you did catch the speaker wires.
Switch your multimeter to DC voltage for testing which output goes to the positive terminal of the speaker and which one goes to the negative:
  • When your reading is negative, it means that your speaker wire with plain color should connect to car radio wire tested with the black lead, and the one with a white stripe goes to the car radio wire that you just tested with the red lead.
  • When positive, it's the reverse case of the above so the speaker wire with a white band goes to the car radio wire that you just tested with the black lead of the multimeter.

Fitting a car stereo radio and modifying the existing wiring

Wires identification will allow you to compare the existing car radio harness in your vehicle to the connector at the back side of the car stereo:
EXISTING CAR RADIO WIRE HARNESS
CAR RADIO FEMALE CONNECTOR AT ITS BACK SIDE
Now you need to modify the existing in-car harness in order to mount the male connector that comes with the car radio, in case it's not the same. Do not hesitate to cut the wire harness but leave 3 inches of wire length, in order to be able to use again this connector on another vehicle, or to refit it in your car im case you change again your car stereo or take it to another vehicle:
You can now replace the connector you removed, with the one provided with the car stereo and complete your radio installation:

See also our other pictorials for car speaker installation