If you are able to start the car by crossing the starter wires, and it RUNS after, then it should be pretty simple. Get out your wiring diagram and follow the starter signal from the ignition switch (or even before) to the solenoid on the starter. There will be a ton of connections, a couple fuses, and a relay along the way. Get your pointy test light and probe the wires along the circuit to check for 12v in the start position. You could save some time by checking the relay and fuses first; they are usually the problem.
FYI: A relay controls a large amount of power (amps) with a smaller amount. If you were to run all of the power going to the solenoid through the ignition switch, you'd fry your ignition switch in a hurry with all that juice. The ignition switch in start allows a small amount of power to go to the relay that turns on a bigger switch, going to the starter solenoid. It's like a mini-solenoid. Most relays have five pins going to five wires, and almost all of them have the following circuit numbers:
85: This wire brings the small amount (low amps) of 12v power needed to turn on the big switch upon demand. It is hot only when you are throwing the switch (starting the car).
86: This wire is the ground that the small amount of switching power goes to. It is always grounded.
30: This wire is hot almost all the time (in run) coming from a big fuse or fusible link. All the juice flowing through the big switch flows from here.
87a: This is what 30 connects to when the switch is off. It should be a dead wire, connected to nothing in the case of the starter relay. (Other relays might have it going somewhere.) It should NOT be grounded.
87: This is where the mega juice goes when the switch is on. This will go to your starter solenoid.
Unlike a lot of electrical stuff, relays have real moving parts inside. They go bad all the time. Fuses are pretty basic. Too much juice, and the little connecting wire breaks, cutting off the juice.
If you feel really hopeless, you could always just run a wire from your battery to a fuse, then to a push-button switch inside the car, then to your starter solenoid. I would not recommend this, and I am not liable if your car is stolen (A thief would still need to turn on the PCM and bypass the steering wheel lock). But I would be lying if I said I never did it. :-)
Monday, April 30th, 2007 AT 4:55 PM