That was a tough one for me. It would be easy to screw it to the outside of the box that holds the battery and relays, but I did not want to expose it to the elements any more than necessary. Under the hood is tight and if you mount it above the battery, you would have to remove it if the battery had to come out. I found a small amount of space under the main harness that runs into the compartment under the hood. There is a cavity that the harness is in that looks shallow, but if you can get the harness up a bit that channel is pretty deep. I pulled up all six of the relays of their studs that are on each side of the channel and the one down in the left corner and whatever else was holding the harness down. You can hold the solenoid in place and bolt it to the side of that box. I ain't gonna lie to you... It is tight getting it in there, but it will go. You will also have to bend your black and red wires a little on the end so the wires come up more than off to the side.
If you look at the #1 in the green circle in the picture below, that is the solenoid.
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