I do, I even tried it the other way too just in case 
You can't just "try it the other way in case" - if you have done that then you have damaged the driver transistor and possibly other things with almost 100% certainty.
Please excercise great caution with electronics as massive damage can be caused very quickly.
"Bad coils" NEVER - repeat - NEVER just lock on by themselves, it is something driving them that causes this.
