You may reduce downtime by providing techs with repair videos they can access from their smart phones. If possible, set up an area on your corporate website where you can list the videos, even if they're hosted on YouTube and/or made by others (e.g., manufacturers and trade associations).
A poorly made video is more annoyance than help. Before you begin making your own videos, look at what others have done. For example, do a search for some how-to instructions on your car. Note what you like and don't like.
Plan your video before you just start shooting. Walk through the repair process, writing down the major steps. How will you show each step? What do you need to say about it?
In her ebook, "Camera Ready," Manoush Zomorodi provides a wealth of information on making a good video. A couple of her points:
There's a learning curve, but don't worry about perfection. Worry about that tech who needs to know how to repair the equipment. You can always redo the first few videos.