make sure the small wire is hook to the post
Bad battery, bad solenoid, bad cables.
Check the 96 Caddys starter solenoid. Also check the wiring between the battery and the solenoid for any breaks or loose connections.
Seized engine? Loose or cooroded battery terminal Bad starter solenoid? Bad neutral or clutch safety switch?
If your '99 Maxima will not start even after you have changed the starter, you might have a dead battery or a bad starter solenoid. You could also have an empty gas tank.
I know you've replaced the battery and starter and that is usually the problem when it clicks. Have you replaced the battery/starter cables? Still sounds like a bad connection. Although it is a bad connection the question is where? The circuit that is failing is the circuit that pulls in the starter solenoid. This would be the circuit that goes through the key switch from the battery and then on to the starter solenoid. The actual problem is probably a high resistance in the somewhat old key switch preventing the 'full' current from going through to the starter solenoid. Never fear though there is a 'clicky starter fix' (search words) that is available on several sites including ebay. How it functions is to provide a high current relay that is activated by the key switch circuit and transfers power directly from the battery to the starter solenoid to provide full current thereby fixing the problem since the relay does not need 'full' current to activate. This actually works pretty well and if you understand the wiring of the key switch circuit and wiring of relays, you can do this yourself for a minimal cost (for the relay)
Check your alternator and your connections form the battery to the Starter. You may just have a bad connection If that does not work, your solenoid on your starter has gone bad, a new solenoid or starter may be needed. Check the start switch on the clutch pedal if so equiped.
A low or dead battery will have this effect. There is enough juice in the battery to activate the solenoid in the starter (causing the clicking sound), but not enough to turn over the engine. A jump start or a replacement battery may be needed if the battery is no longer capable of holding enough of a charge even when being jumped.
Solenoid could be installed incorrectly. Could be electrical connection on the solenoid. Did you re-connect the battery? Could be a bad starter motor...or a stuck starter motor. Sometimes a light tap or two on the starter motor (not the solenoid) with a hammer will free it up.
Check you connections make sure there on the correct way.
usually this means that your solenoid needs to be changed
You have something on that is pulling power from the battery. Can be any light on the car. Dome, curtsey, under hood, trunk, glove box, etc. Can also be a relay that is stuck.
The problem lies in the starter solenoid/relay system and sounds like the relay is faulty or a wire is disconnected. Follow the positive cable (usually red) from the battery - the other end should be connected to the solenoid/starter.