Logically, you know the car did not suddenly develop a dozen totally different problems, so look for something all those circuits have in common. The first thing to consider is the Ford engineers like to run the ground wires for many circuits into a single terminal that gets bolted to the body sheet metal or engine. Look for a ground terminal that is rusted off first.
Also follow the various wiring harnesses around to see if one fell down onto hot exhaust parts. Melted wires usually affect different circuits at different times, but if a twelve volt feed wire is affected, that can cause a fuse to blow that feeds many circuits.
Also, consider that some time in the past, a mechanic may have needed to unplug a connector with many wires in it. It is common for the locking tabs to become brittle and break off, and it's not unheard of for a connector to be hard to reconnect, and it may feel like it snapped together when it really did not. It can take minutes, days or years to pull apart from the normal rocking of the engine. A loose connector between the body and engine or the body and transmission can cause a failure in multiple circuits. Also, look for corrosion between multiple terminals inside a connector. When that corrosion gets wet, it will conduct current from one wire that has voltage on it to an adjacent wire that is supposed to be turned off. Both circuits can do the wrong thing resulting in multiple fault codes.
Tuesday, January 3rd, 2017 AT 1:44 PM