98 Merc Tracer has automatic transmission. Sat all winter unused. But started right up at first 2 uses days apart form each other (short uses only down a driveway and back) after winter.

The shifter has a push button on side and you slide it into P N D R etc. Shortly after parking it and turning off the engine, went just within moments to re-start it and there was no noise at ignition. Nada when I turned the key, as if battery just went dead very suddenly. I did consider it might have only had a couple starts left in battery and the short uses didn't let alternator recharge battery, so it might have gone dead, but that seemed awful sudden.

So I thought, maybe it's not exactly all the way in Park, so I depressed brake, push in button on shifter to shift and take it from where it appeared to be in Park back to I think maybe N, and then back into P, trying this time to make sure it is fully in Park. Still no noise when I turn the key. I left then, as I didn't have to use that vehicle that day.

Came back today and same thing--no noise when I turn key-- except NOW I can't even move the shifter out of park. I can depress button but the shifter won't budge AT ALL.

What did I screw up and how might I fix it? I was trying to get it into neutral to push car into position so I could jump start the battery with another vehicle, in case that was the problem. Now I can't shift it at all or move it since I can't get it out of park.

Extra info: I did find a mouse nest under hood but can't see anything mice chewed wire-wise. I cleaned that out.

Begin by removing and fully charging, or replacing, the battery. Then, clean the battery terminals and cable connections thoroughly. Ensure cables are in great shape.