Okay. See if you can make sense out of these. The first one shows the wire colors, and the parts are labeled. This is from a "Notes Pages" handout I gave to my students. It looks real complicated because of all the things I added. The second one shows just the ignition switch and neutral safety switch turned on. The lame-brained engineers added a Rube Goldberg circuit by adding the Engine Computer, (PCM) in the same circuit as the neutral safety switch. That means you can no longer perform a simple, quick resistance test to see if the switch is working properly.
In the third drawing, the relay contacts have clicked on and current flows through the two coils in the solenoid. Some current goes right to ground, and some goes to ground through the very low resistance starter motor coils. The magnetic fields of the two coils are strong enough to engage the starter drive gear. The solenoid contacts turn on at the same time.
In the last drawing, the high starter current flows through those contacts, (which cause a lot of trouble), and through the motor, to ground. Full battery voltage is on both sides of the Pull-in coil so it turns off. It isn't needed once the drive gear is engaged so by switching it off, that current is available to the starter motor. That might make the difference between starting and not starting on a cold day or with a marginal battery.
May, 13, 2011 AT 12:20 AM
I took took out the ingnition switch and found a small piece of metal. It broke off from the small metal shaft that sits behind the key cylinder. I suspect that the piece would engage from time to time and then bend just enough until it finally broke off. I hope this is the case. It was easy to take this all apart. Going to the junk yard to get another part. I will update you to the status when I get it back together this weekend.
May, 15, 2011 AT 3:59 PM
Problem solved. Changed the ignition switch along with going to the junkyard and getting the plastic shaft/metal prong assembly that was borken. Car has been starting fine ever since.
THANK YOU for all your help.
May, 16, 2011 AT 8:10 AM
Sorry for taking so long to get back. My main computer stopped getting access to this site so I'm on a miserable laptop right now.
The dealer has a repair kit for the lock cylinder. It's called a "cam repair kit". You break the old cam off, slide the new one on, and drill a small hole to slide in a roll pin. Did that on a few including my mother's Grand Caravan. Only takes about an hour and you can keep your old cylinder and ignition key. I didn't think of that earlier because I never saw one be intermittent. The typical symptom has always been everything else electrical worked except it didn't turn the switch quite far enough to crank the engine.