If the inertia switch test's ok then you will more than likely need to replace the central junction box. The relay is located inside and is not serviceable alone.
Price dropped to $6500.
This is a complete engine with turbos ready to be dropped in. EGR is deleted. I will sell it without the new pump and injectors for $5000.
I have a 6.4L engine for sale. It has 44k miles. Has new injectors, HPFP, oil cooler and new head gaskets. I am in Fort Worth. I can deliver local or can install it. Asking $7500.00