Gregory,
Sorry to hear about your trouble, that is super frustrating.
I would first check to be sure the 1/4" cable from your blue box to your amp wasn't the culprit. Then I think look at the 5-pin cable. That's probably the least robust part of the entire system as it gets constantly flexed, coiled, uncoiled, stepped on, etc. Examine every inch to be sure it hasn't been run over and cut. Then plug it in with the bass on and flex it all down the line to see if you can find a spot which stops the sound. When my old/new Belden cables failed it happened about a foot from the bass where the wire bent through my strap and down towards the floor. I could bend the cable there and the bass would turn on and off. (If it's power you're losing, it can send a huge audio spike down the line so don't have your amp turned up too loud.)
Don't forget that you can also switch to the 1/4" jack in these situations.
Do you have a 2nd 5-pin cable?
Jimmy J