'08 Cobalt - Install 228VX Kit wiring help?

So far I’ve mounted the compressor to the trunk and drilled a hole for the 1/2" air hose to run to the front of the car. I haven’t wired anything at all yet. Whats got me stumped is the grounds and switches and all that jazz, I’m mounting the solenoid valve in the front under the hood along with the 4 horns. I don’t understand at all where the red 10ga wire goes or the grounds or where to splice in the switches and to what wire, and where the blue 18ga wire goes. I haven’t taken apart one of my cigarette lighter switches yet so I don’t know if they have a ground or what but they stay on regardless if the car is on or off. I bought a switch to run from that to my compressor to toggle when I want it on so it just doesn’t run constantly. The second switch I have is to “honk” the horn, and I know it has to be run to the valve somehow but where does the other end have to be run to? haha help me out

I should add, my battery is in my trunk, so the wires to the compressor reach right to it.

Welcome to the forum. There should be threads in “Your Horns & Installs” that have links or attachments to schematics.

I realize your kit probably didn’t come with a relay, but here is Viair’s diagram for a light duty compressor. Pick up a relay at the part store to be safe and follow this schematic.


Use your 10ga wire from your battery to the relay & to the compressor. Your 18ga wire can be used for the trigger/coil side of the relay. It can also be used for your horn solenoid.

If you want to splice in a master kill switch, put it between the ignition source and the pressure switch. The pressure switch handle turning the compressor on & off.

You will have a couple grounds. Attach the wire to some bare shiny metal on the vehicle - preferably with a ring terminal and a bolt.

The horn wiring to the solenoid goes like this: Positive source—>into switch—>out of switch—>into solenoid (either wire)—>ground other wire.

Let us know if you have any more questions.