No crank - no start

1994 4.0L/AW-4

I just went out to the Jeep and it would not start. I have a pair of driving lights wired directly to the battery, and they had power. The stereo, on the other hand, did not have power. So I believe the battery (red top Optima) is still good.

When I turned the key to start the Jeep, the motor did not crank over. All I got was a very rapid, fairly loud (all I can come up with is heavy clicking). It did not sound like a relay to me, it sounded heavier. Maybe the starter?

From the basic description, does anyone have any ideas what I need to fix? Or have questions for me to answer?

*EDIT*I just pulled the check engine light code and got error code 12. Now I'll look that up and see what 12 is. Oh, and the lights didn't work this time. I don't understand the Jeep thing.*EDIT*

Thank you for your help.

well phil not to bust your bubble but actualy it is the cheaper of the two parts . it is the relay. but to put your mind at ease and make sure i am right. if you have a digital camera. take a picture of the starter relay. (behind the battery) and e-mail it to [email protected] the affirmitive diagnosis for this without just replacing it is visual not mechanical. i had the same problem with my 90 4.0. i had the same exact symptoms i hade Hella aftermarket lights on front wired directly to the battery. and an aftermarket CD deck. lights worked deck didnt. and believe me it is a very heavy sound. there is a coil inside the relay and the points in there are heavy duty. the relay is like $24.99 versus the extream price of the starter. the guy at the parts store showed me the visual check which is much more easy than the chilton daignostic procedure. he has a 91 4.0.

p.s. make sure you in the picture you can see the bottom edge of the relay and take the green wire on the bottom left off and try to get it as clear as possible. take several if you need to.

If you dont have a digital camera or know someone who does. just send me a private message and i will walk you through the visual check.

If the starter solenoid is chattering, the first thing I check is battery voltage and then the battery cables, to include the ground at the block and the big nut on the starter. A low battery will make them chatter, as will poor connections. There can be some other problems, that will cause solenoid chatter, but these are the most common.