My 99 Bonneville Vin K is not starting or cranking. It acts as though I have low voltage. Even being jumped it does not want to start. It has a brand new battery and starter barely a few months old. so the positive terminal was kind of loose so I just switched with another, and it'* pretty tight now, nothing wiggles and everything turns on. All the accessories work, radio, windows, seats... so its not the BMC. The security light goes out when supposed to so I don't think it has to do with vats. although the battery was unplugged for a while and reset everything, so is there something I must do to reprogram? I checked most fuses and relays, could still be one but which one?

So when I turn the key everything is normal then I crank it and it only gives me one click like low battery, as though the solenoid is activated but the starter doesn't turn.

Anyone know what this could be?

It could be any number of things, but you will want to narrow it down by getting under the car, checking for main power at the starter (the big wire), and power at the starter trigger wire when trying to start. If you are getting power at both, check the second large wire running from the solenoid to the motor to confirm power. If you are getting power at all 3, the starter is likely bad, or you have a major grounding issue (doublecheck grounds to rule this out).

If you are not getting power somewhere you should be, post back with your findings so we can help narrow the search a bit.

that was it. thanks! for whatever reason it wasn't seated well on the battery, i just reinstalled the terminal. looked like some striped rubber could have stopped it from contacting. works now thanks a bunch.

edit: from quote it wasnt the large wire from solenoid to motor, it was large wire from battery to starter.