Field not appearing on field mapping with CRM

Field not appearing on field mapping with CRM

I am trying to create a form for employees to fill out what services were done to a vehicle.
But for some reason the vehicle field is not appearing on the CRM field mapping options.

CRM Field Mapping Options not showing the Vehicle Field


The fields on the Service History Module



I added the Vehicle as a CRM field then auto mapped it to a single line field so it could be used in the integration page.