I lot of the problems people are having on here relate to simply not being methodical about the build / install / config process. I know it's exciting, you've got a new toy, at a bargain price. But you need to read and re-read the documentation, don't rush things, approach it like the chippy's old adage "measure twice, cut once". (please don't cut your IEBC )
That said, I think the Autospeed/Jaycar documentation IS somewhat lacking, it's aimed at Electronics enthusiasts with Cars, not Car enthusiasts who can hold a soldering iron, which seem to be the majority of its consumers.
Personally i had very few dramas, and am very happy with the product, one day i'll get around to better integrating my install rather than having to manually switch it ON/OFF by earthing it to the cigarette lighter.