Does the speed controller auxiliary power post produce enough voltage to switch two turnouts connected to one switch? Is their another way to control these turnouts other than off the speed controller post and the provided switches?

I'm new to railroading and need some help with the turnout switching. We bought 5 yo son the "Golden Spike" and  "Your First Railroad Track Pack" for Christmas. I've connected the Track Pack" as shown on the layout on the back of the box. Basically, and oval with an inside loop on one end, and a turnout to back the cars into splitting into two tracks with bumpers. The layout has 4 electric turnouts and two switches (what's that about). The "Golden Spike" had one manual turnout and 1 electric switch (what's that about). Also, I usually do things in a big way so I'm building the whole table as shown in the DVD with mountains, buildings, roads, etc.. The question, four turnouts, three switches, I connected the two turnouts to make the inside loop together, plugged them into one switch. It also makes it easier for the 5 yo not to forget and only switch one. Yesterday, the two turnouts worked together fine. However today, one will only switch one direction. I substituted a different turnout, same thing. Substituted a different switch, same thing. Checked where a stripped and tied wires together, no luck. Any suggestions, what am I not getting?