Under my van , directly under the tranny, near were the front drive shaft is. I scraped off what ever was there and was attached to the tranny. I now have the wire with the plastic connector hanging under there.(On the drivers side of the tranny) I think it may be some sensor that detects if the front shaft coupling is vibrating, but maybe not. No lights are lit in the dash. What is this part called? and were do I get a new one. Or does it not matter. MK

it matters very much, every sensor effects the car. Air/fuel ratio and possible damage or overheating to the the engine block, or cooling system are run by sensors. If no lights have turned on, it could be a bad switch or PCM.