The devil's in the details...
The devil is definitely in the details when it comes to wiring. I thought I had everything correct on a Silverado I was rehabbinbg last month. It turned on and ran great without any attachments, but when I hooked up a hose and a power nozzle, I discovered I had two wires reversed on the cord winder, which caused the power nozzle to run when the machine was off and vice versa.
If you don't own a multitester, you should definitely invest in one so you can detect the short and open circuits. I'm personally more fond of the older analog meters but you can pick a cheap digital model up from Harbor Freight for about the cost of a hamburger. Sometimes they will even run a coupon to get one for free with any purchase.
Just out of curiosity, did you test the motor before installing it to ensure it is indeed working?