Welcome to irv2.
If your display is on the Workhorse chassis it is a Actia display, this link
will give you the instructions to get it replaced from Actia.
The coat will be about $375 and the old one has to be sent back to them to reset your mileage on the replacement unit.
Dependent on your dash it may only require the removal of some screws to remove from dash.
Your jack alarm maybe a jack that has not returned to the stop position due to weak springs or a defective sensor at the top of jack piston.