Where To Get Service Information
When you perform any diagnostics it's not much good to get, say, a voltage reading if you don't know what the correct reading is supposed to be. And testing has become an exact science. Diagnostics have to be performed in a certain order or the test results you get could very well be meaningless. So you need to find the latest factory diagnostic sequences and specifications.

Some vehicle manufacturers have web sites with this service information, and you'll be able to access the data on a daily, weekly, monthly or annual basis.

But, as my Grandfather used to say, there is no such thing as a free lunch. There is a charge for this information. At present, Ford Motor's information is available for $9.95 for a 72-hour access period at Motorcraft Technical Resources.

GM offers a similar program at their ACDelco Tech Connect web site. Or you can get a low-cost subscription from Alldata DIY. In addition; AutoZone offers free scan tool connections and readouts at its stores when you have a lit MIL.

A great place to get service information for free is your local Public Library. The Reference Section has all the different service and repair manuals from Chilton, Haynes, Motor and many others. If they don't have the one you need, ask at the Reference Desk and they will get it from the main branch.

Many public libraries subscribe to online services like Alldata and Mitchell On Demand and can print out the information you need.