Hard to tell from your post but it kinda sounds like you (or someone) put a 4 wire solenoid on your 149, is this correct? If so it will work but it may not be hooked up right.
If it's been working ok up until now and it all of a sudden it doesn't... Check the safety switches on the PTO and brake pedal.
If those things don't help any, go here,
http://www.onlycubcadets.net/forum/showthread.php?t=22
Using your test light, start at the battery and work your way through the system until you find out where electricity should be but isn't.
It would also be helpful if we had a little history on the problem... (Has it been doing this off and on for awhile, have you changed any parts, have you had the tractor long or did you just get it) What ever information that could be of use to help diagnose the problem... It's really hard to help with a problem over the internet without specifics.
There are a lot of knoledable people here who are eager to help, and not very many who will laugh at anyone just because they aren't well versed about something.
Good luck and welcome to the forum.