I have a 85 240 wagon that has been slowly draining the battery for a few months now. I disconnected the battery cables and installed a new battery. Upon re connecting the battery cables, the alternator went up in smoke. I thought that maybe it had an internal short so I replaced it with a new one and I am getting the same thing. I am on the third new alternator and whenever I try and connect the battery cable the alternator goes up in smoke. This is happening when the engine is not running and the ignition is off. Please let me know if anyone has any suggestions. All the connections are correct and good and the grounds seem ok. Any help is appreciated.

 

This is a polarity problem.
Triple check your connections. ALL of the connections.
Ed