08 Hummer H3 installing Valor NVG-720W with GMOS-01 to retain Onstar and door chimes. I have NO factory amp but installing aftermarket comps and coaxials that will be amplified as well as sub/amp combo. In the section "for aftermarket radio and amplifier" here's how it reads

FOR AFTERMARKET RADIO AND AMPLIFIER
(See wiring diagram on page 6)
CONNECTIONS TO BE MADE ON THE 14 PIN HARNESS:
1. Connect the red wire to the ignition/accessory wire of the aftermarket radio.
2. Connect the Orange/white wire to the illumination wire of the aftermarket radio. If the aftermarket radio
has no illumination wire just tape off the orange wire.
3. Connect the blue/white wire to the amp turn on wire of the aftermarket radio
and to the blue/white wire in the 24 pin harness.
4. White NOT USED
5. White/black NOT USED
6. Gray NOT USED
7. Gray/black NOT USED
8. Connect the Brown wire to the mute wire of the aftermarket radio. If the after market radio does not have a
Mute wire, tape up the Brown wire.
The following wires on the 14 pin harness are for the aftermarket radios that
have navigation built in:
1. Connect the Green wire to the parking brake wire of the aftermarket navigation radio.
GMOS-01
4
Continued:
The following wires on the 14 pin harness are for the aftermarket radios that
have navigation built in:
2. Connect the Blue/Pink wire to the VSS or speed sense wire of the aftermarket navigation radio.
3. Connect the Green/Purple wire to the reverse wire of the aftermarket navigation radio.
When completed, plug the 14 pin harness into the GMOS-01.


CONNECTIONS TO BE MADE ON THE 24 PIN GM HARNESS:
1. Connect the yellow wire to the radio’s 12 volt battery or memory wire.
2. Connect the black wire to the radio’s ground wire.
3. Connect the blue/white wire to the amp turn on wire of the aftermarket radio and to the blue/white wire of
the 14 pin harness.
4. Connect the green wire to the amplifier’s left rear positive speaker output.
5. Connect the the green/black wire to the amplifier’s left rear negative speaker output.
6. Connect the purple wire to the amplifier’s right rear positive speaker output.
7. Connect the purple/black wire to the amplifier’s right rear negative speaker output.
8. The Orange and Orange/White wires are not used. Please tape up wires to avoid a short circuit output.
9. Cut the white wire about half way between the two plugs. Connect the white wire from the 24 pin plug to
amplifier’s left front positive speaker output wire. Connect the white wire from the 12 pin plug to the positive
speaker wire of the Metra SP-2003 or equivalent.
10. Cut the white/black wire about half way between the two plugs. Connect the white/black wire from the 24
pin plug to amplifier’s left front negative speaker output wire. Connect the white/black wire from the 12 pin
plug to the negative speaker wire of the Metra SP-2003 or equivalent.
11. Cut the gray wire about half way between the two plugs. Connect the gray wire from the 24 pin plug to amplifier’s
right front positive speaker output wire. Connect the gray wire from the 12 pin plug to the positive
speakerwire of the Metra SP-2003 or equivalent.
12. Cut the gray/black wire about half way between the two plugs. Connect the gray/black wire from the 24 pin
plug to amplifier’s right front negative speaker output wire. Connect the gray/black wire from the 12 pin plug
to the negative speaker wire of the Metra SP-2003 or equivalent.
Note: If only one SP-2003 is used tape up the gray wires that would normally connect to the second
SP-2003 to avoid a short circuit.

My question is about the 24 pin harness where it speaks of connecting to amplifier speaker out wires(numbers 9-12); is that if I am using the stock speakers? I am swapping stocks for comps and coaxials

One other question, what is the VSS or speed sense wire in the HU harness? Is there another name for it, mine has none marked as such