Try shifting to neutral, then see if it cranks.
A common problem is worn contacts in the starter solenoid but that would make one loud clunk each time you turned the ignition switch. If you don't hear anything, we can rule that out. Start by locating the starter relay under the hood, in the fuse box. You MIGHT be able to feel it click if you put your finger on it while a helper turns the ignition switch to "crank". A real quick test of that relay is to swap it with a different one like it. Try the AC compressor or radiator fan relay. They should be the same.
There are four circuits related to that relay. You'll need a test light to check them right at the relay's socket. To get started, ground the clip lead of the test light right on the negative battery post, then probe in the socket of the relay. One pin must have voltage all the time, and a different pin must have voltage when a helper turns the ignition switch to "crank". Holler back with those findings.
Friday, December 10th, 2010 AT 5:30 PM