[PKRWUD]

You'll need a non powered 12 volt test lamp ($3 at Pep Boys). Do these in order, and stop if it fails a test.

First test:
Attach alligator clip from test lamp to engine block, and touch the tip of the tester probe to the positive battery post.
Lamp should be bright.
If not, check your grounds from the battery to the engine.

Second test:
Leave alligator clip attached to block, turn the ignition on, but don't start it. Touch the tester probe tip to the positive post on the coil.
Lamp should be almost as bright as it was for the first test.
If it's not lit, the problem is an open in the wire between the key and the coil.

Third test:
Move the alligator clip to the negative post on the coil.
While you are holding the tester probe tip to the positive coil post, have an assistant try to start the car.
The test lamp should pulse on and off, repeatedly.
If it doesn't, then no signal is getting to the coil from the module.

Fourth test:
Attach the alligator clip to the block again.
Turn the key on again.
Pierce the red wire at the module with a safety pin, and touch the tester probe tip to the safety pin.
The lamp should light up as brightly as it did for the first test.
If it doesn't light, there is an open in the red wire between the module and the key.

Fifth test:
Remove the cable that goes to the starter from the starter relay, at the starter relay (one nut).
Pierce the white wire at the module with a safety pin.
While you hold the test er probe tip to the safety pin, have an assistant turn the key to the start position.
The lamp should light up.
If it doesn't, there is an open in the white wire between the key and the module.
If it does light up brightly, the module is bad.

Take care,
-Chris