LarryD:
It is very important the coil wires are connected in the right order.Also, use a DVM and check there are not any open coils.
I feel like I've tried almost every one of the 24 permutations of four wires by this point, but in my research I've found that 8 of them should work, since you only have to get the right pairs (though it may not go in the right direction). I've since paired up pin 1 with pins 2, 3 and 4, and all of them result in vibration. I have a DVM and I got an A in my Intro to Circuits class 2 years ago, but I'm really not sure what to test with respect to the wires, although I've only spent about 15 minutes researching that (ongoing).
LarryD:
BTW
If you are trying to power the motor with the Arduino, don't!You need an external 5 voltage power supply fo the motor.
I thought that using an Arduino to power a little 28BYJ-48 with no load attached to it would be ok. If not, that's just one more reason that my professor is awful since a power supply wasn't in our equipment list. He did have us buy 9V battery strap, but I'm a little hesitant to just directly connect a 9V battery to my motor.