OK lets back up.
on a stock FZJ80 there is no CDL switch, the CDL locks up when the T-case is shifted into low.
There is a switch on the T-case near where the shifter goes in, after the shifter has moved from the high range gears to the low range gears this switch sends a signal to a relay, the relay see's this and powers the CDL to lock, that signal comes into the relay on a blue and black wire to pin number 7 hence the name of the mod, the only way to unlock the CDL is to go back to high range so stock you have two options,
High, CDL unlocked
Low, CDL locked
When you add the CDL switch you can then hit the switch to lock the CDL at any time, so you can lock the CDL wile in high range, so now you have three options
High CDL open
High CDL locked
Low CDL locked
But you still do not have the fourth because not matter what the switch position when you shift into low the signal travels down pin 7 and the CDl will be locked,
If you remove the pin 7 signal than that that relay will never see the T-case go into low so it will never automatically lock the center, now with the CDL switch and pin 7 mod the only way that the center ca be locked is via the CDL switch so you have 4 options and complete control of CDL operation.
High CDL open
High CDL locked
Low CDL locked
Low CDL open
T-case gear range and CDL operation are now completely separate and under your control instead of tied. I see why Toyota did it this way, would be hard for the average person who is used to only cars to get their head around a low range much less throwing the mysterious center differential thing in so they took it out of the drivers hands and made it automatic.
If you did the pin 7 mod before getting a switch then you could not lock the center, you would have two options
High, CDL open
Low, CDL open
If you have front and rear lockers you would not be able to lock those either as they require the center to be locked.
Personally I like the real CDL switch even if pricey if only because it has the backlit CDl symbol on it that matches the light, having two hazard switches seams improper to me.
. Just another thing to taunt my Jeep friends with 
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