What did I do to my car?

[fooss0le]

I drove my 83 300SD up on ramps to troubleshoot a problem with speedometer working only intermittently. I removed the speedo sensor then put it back in. Now the car will not turn over. It is an automatic trans. All fuses in the fuse box look okay and there is electrical power. All things (that I know of) function except the car does not even try to turn over. I would think that there is a detector that is tripped when the trans is in park but I cannot find it. What did I do to my car?