The weather where I live has gotten fairly cold and my car was starting to have problems starting (slow weak crank).

After a few days of the car turning over progressively slower and weaker eventually the car wouldn't turn over at all. I would hear this pulsing sound (sounded like electricity was flowing) when turning the ignition but I didn't hear any clicking sounds.

Figuring the problem was the starter anyway I replaced it but encountered a huge problem. The starter was spinning when connected to power even without the ignition on or even the key in the ignition at all.

After doing a little digging I figured that the new starter had a faulty solenoid and so I exchanged it.

After installing the second new starter the same thing happens!

The instructions say that the solenoid cap can be damaged if the positive cable is put on too tight but the first new starter was not that bad and I made extra sure that the second was fairly loose (within reason).

Any help would be greatly appreciated. Thanks in advance!