Owner's Manual

3
Locating 12 volt Resistive Control Wire (Versions 1, 2 or 4) Green Wire Applications
1) Using a multimeter set to test DC voltage, attach the black test lead to ground and the other to the
suspected wire.
a. With the factory radio connected:
i. Have the SWI disconnected and the ignition on. You should read 0 volts when not pressing
buttons. When pressing buttons, you should get a DC voltage reading for every button press.
When you test the control wire, every button will read a voltage that will be unique to that
button. If you unplug the connector from the radio and no longer see any voltage readings
when pressing buttons, there is likely a wire that the factory radio provided voltage to the
steering wheel control circuit and since the factory radio is no longer connected, it will need 12
volts provided to that wire to receive a reading on the control wire. Below is an example of a
2009 Chevrolet Malibu SWI wiring instructions that indicate what wires are used in this
situation:
For this situation, the Dark Blue in Pin 11 of connector 1 should have tested as your control
wire. With the factory radio unplugged from the harnesses, you will no longer receive any
voltage reading on the Dark Blue wire when pressing buttons, since the radio is no longer
providing voltage to the White/Black wire in Pin 14 of the connector 2 harness. To test for the
correct voltage supply wire, set the multimeter to test resistance and place one lead on the
wire that you verified is the control wire, and the other lead on the suspected supply wire.
Pressing steering wheel control buttons should yield a different resistance reading for each
button press. Since you have verified the control wire and the supply wire, you can now
connect the green wire from the SWI to the control wire and connect a wire supplying 12 volts
to the supply wire on the radio harness
b. With the factory radio disconnected:
i. Have the SWI disconnected and the ignition on. You should read 0 volts when not pressing
buttons. When pressing buttons, you should read close to ignition voltage, or in some cars,
approximately 5 volts. If the voltage does not read 0 volts when buttons are not being pressed,
this is not the correct wire to tie into for this type of circuit. In some instances, it is possible to