Let me preface this by saying I'm of the understanding that Mausberry's switches are a great solution, but their customer support is nonexistent. Heck, it took me over a week to get any valid tracking data after my order was confirmed. /rant
The issue I'm having is this: I have a Mausberry 2A Car Switch (http://mausberry-circuits.myshopify.com ... ply-switch) wired into my car's glovebox fuse compartment via a pair of fuse taps. One of these taps pulls a constant 12V from the battery, even when the ignition is off. The other tap is wired to a fuse dependent on the ignition status. That is to say it only supplies it's 12V after the car is started. In addition, there is of course a ground. When the switched fuse has power cut/supplied, it's supposed to trigger the Mausberry's circuit and supply 5V of power to a female USB port (where the Pi will be powered from). Everything in this system works great for about 90 seconds after startup. Unfortunately, at that point, the Mausberry switch abruptly stops supplying a 5V source to it's USB port.
Using a multimeter, I've confirmed that the aforementioned fuses are supplying enough power consistently. Having monitored their voltages with the ignition on for over 2 minutes each, I saw <.2V fluctuation from the norm (never dropping below 14V). There were no noticeable dips or spikes.
I then sacrificed a spare USB cable to test the voltage coming out of the Mausberry circuit. After several identical tests, I observed a consistent 5V supply for approximately 90 seconds. After that 90 seconds, the 5V supply dropped to 0V and never returned.
Having tested multiple fuses for each wire, I am absolutely stumped. I can't think of any hardware-related design in the switch that would be switching it off after 90 seconds. Is that even possible? What else can I try to troubleshoot?
I'm itching to get this problem sorted, as the car power supply/safe shutdown switch is the last piece in a personal project I've been working on for almost a year now. I'd appreciate any guidance or advice! Thanks in advance!