Ignition interuptor

Ok...im driving home from work and hit the turn signal to turn, and then the speedo and tach go to zero.  I was like WTF!  Roll to the side of the road and try to restart.  fires then dies. that bought my attention to its the ingition interuptor. So after i call up step dad to bring the tow rope and truck, i check out the ing interuptor system that the past owner installed.  Find that its just a jumper into a box, took me awhile, since its slightly snowing and winds were howling making it feel like 10*F.  I plug the factory connector in and try to start it..just as step dad pulls up..starts up.

My question..wtf made it turn on and turn the engine off?

I checked the fuses all around inside car and in the engine compartment. non blown.   Connections looked/felt like they were in tight.