Not to forget that some 4-pin power connectors connect to the motherboard, using the traditional 3-pins plus a PWM connector.
I looked at my setup again and this is what I have:
The front and rear 120mm fans have the large 4 pin connectors that plug into the PSU. The side door fan has that same connector. However, the front and rear fans also have a small 3 pin connector with 1 wire running to it.
My motherboard only has one 4 pin connector for system fans. I figured that the three fans plug into the PSU line and then that has a small 4 pin connector at the end, which I guessed plugs into the four pins on the motherboard. However, that would leave the 3 pin connectors unconnected from the front and rear fans.
How should I proceed?