The ignition switch has three or four separate switches in it. If it was just one switch, everything it controls would work at the same time. That means the starter would crank constantly while you were listening to the radio or just driving. Just because you hear the fuel pump, (which is a valuable observation), that has nothing to do with the part of the switch that turns on power for the power windows, heater fan, and radio, and the "crank" circuit has nothing to do with anything else.
On your car the ignition switch is not a common cause of cranking problems, but it should be pointed out that it still has the switch on the lower steering column. Those are adjustable. If the two screws come loose the switch can move down too far to the point where you can't turn the key far enough to get it to the "crank" position. Something similar often happened on the '90s Escorts. At the end of the ignition lock cylinder was a small, wimpy screwdriver tip that turned the switch. If that tip twisted, you'd have to turn the key further and further until the point was reached where it would no longer go far enough for the engine to crank.
The point is, and I don't mean to sound sarcastic, saying the ignition switch is okay is like saying the the radio's power switch must be okay because the power locks work.
In the future, stop here first for my wondrous wisdom before you go through all the trouble of removing the starter for testing. Starter motors are the last thing on the list of suspects for a no-crank symptom. There are a number of things that can happen to a starter motor that will not show up on a test bench. The only accurate way to test a starter is on the engine where it will be under load. That will allow us to test the cables too. Ford is one of the few manufacturers that hasn't switched to a gear-reduction starter like Chrysler had since 1960. The direct drive design draws quite a bit of current and that is not replicated on the test bench. With no load on the bench, your starter will typically draw less than 50 amps. However, when it is trying to spin the engine, it can easily draw over 150 amps. THAT will make a loose or dirty connection show up when just running head lights and power windows will work fine.
The only thing we can assume from external testing is the starter motor spins. There's actually two totally separate motors built into all starter motors. If one part fails, you'll never know that on the test bench. On the engine though, it will crank too slowly, and without getting into the electrical theory, it will draw close to normal current.
Ford HAS switched over to a starter circuit that is similar to what Chrysler and GM use. That isn't better or worse than the multiple designs they had in the past. It's just different now, and it's still pretty easy to diagnose. The entire circuit can be broken down into four parts and each part has a test point at the starter relay. Since you obviously are knowledgeable enough to want to diagnose this, lets start in the middle of the procedure. Be sure it's in "park" because if the engine starts, you'll look funny chasing after your car as it drives away on its own!
The engine can only start if the ignition switch is on. Leave it off for this test. Remove the starter relay from the socket, then use a jumper wire or stretched-out paper clip to connect terminals 30 and 87 in the socket. Post a reply telling me if the starter cranks or it doesn't, and if it cranks at the normal speed. If it doesn't crank or cranks very slowly, turn on the head lights, then try again and watch what happens to the brightness of the lights.
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Saturday, March 7th, 2015 AT 8:23 PM
