Well, I fixed the problem today guys. It was indeed the ignition switch.
Today being a Saturday, however - NOBODY had the part in stock, and the dealership parts department is closed. Ugh. So, I was forced to take matters into my own hands.
Figuring I had nothing to lose, I popped open the ignition switch itself. With a little bit of help from a small screwdriver, the black part can be popped off the white part. There are three little "tabs".
There are several contacts in there, as well as a couple of springs that work in a way that is difficult to explain. Basically, the springs hold two contacts that slide in plastic grooves when the cylinder is turned. The plastic groove guides the contacts so they touch the appropriate terminals when the cylinder is turned.
If those tiny, spring loaded contacts are not in the correct position in those grooves, the switch will not work properly.
It took a couple of tries, but once I got those contacts sliding properly in the plastic grooves, the terminals were working like they should. This is verified by checking resistance from terminal 30 to 75. There should be an open circuit with the cylinder in the "off" position, and zero resistance with it "on". Before I took the switch apart, I had an open circuit from 30 to 75 in both the on and off position. Ah ha! :biglaugh:
Terminal 30 feeds terminal 75, which is the one with the yellow/black wires. These, in turn, feed the horn relay, as well as the load reduction relay. The load reduction relay goes on to provide power to circuits for headlights, wipers, turn signals, blower, rear defrost, etc. No power at terminal 75 = no horn, no lights, no turn signals, etc!
Here is the back portion of the ignition switch; it interfaces with the shaft from the key cylinder.
Look closely - you can see a little pin inside the yellow hole. It is spring loaded, and pushing it in results in moving a contact and a couple terminals get powered up (this is the switch that gets turned on for "key in ignition").
Turning the yellow portion is the same as turning the key on and off. It is easily turned with a screwdriver on the bench, so you can test terminals 30 and 75 as described above.
Several of the terminals had a bit of build-up on them, which sanded off quite easily. Also, I can imagine how these ignition switches could fail over time. The metal contacts that slide in the plastic grooves could wear down the pastic over time, allowing the contacts to jump out of the groove. I'm not sure if this is what happened to mine or not...the plastic
is worn a little, but the contacts are now back in place, and the car is working great! Back to normal!
Ray - let me know if you have any questions at all. I have the PDF's of the wiring diagrams and have studied them a lot over the last 24 hours. Also, taking the ignition switch out is very easy, and I'd be happy to help you out with that. It is about a $40 part from a parts store; maybe more at the dealership; maybe less from an online parts web site. I'd imagine you could have the old one out and a new one in place in 30 minutes. There's no doubt in my mind the dealership would charge a "diagnostic fee", then an inflated price on the part, then at least an hour of labor.
To everyone else (and especially kenblasko), thank you very much! In less than a day we developed a very strange electrical problem, diagnosed it, took parts apart, fixed them, and put it all back together. Soooo much more fulfilling doing it yourself, instead of the dealer! Plus it was
FREE!!
I couldn't have done it without everyone's help! Thanks!! :thumbup:
