72 thinline hum on bridge?

I recently built a telecater style guitar and put a loaded 72 telecaster thinline pickguard on it. The neck pickup sounds fine but I notice that if my hand touches the bridge pickup while my other hand is not touching the strings it buzzes pretty loudly. It sounds fine as long as 1. either one of my hands is touching at least one string or 2. I don't touch the bridge pickup. I suspect a ground short somewhere- anything I should look for when I take it apart? (I did run a wire to the bridge) thanks as always

That sounds more like an open ground from the bridge pickup. Like the shield conductor from the pickup isn't twisted together with the ground lead. The guitar should get quiet whenever you touch grounded metal.

Thanks telenator! I'll look for something like that tomorrow when I pull it apart