New to this. I bought a pi-4 kit. It has dual heatsink fans that get connected to pin 4 and 6. however, I want to do other projects and need to connect a ribbon cable to it. how can i do that while still having the fans connected?
Take a ribbon cable, remove some 3 mm of the plastic coating of the wires leading to pin #4 and #6. Then, cut off the plug of the cable leading to the fan, separate the last 10 mm of this cable's wires, and remove the last 3 mm of the coating. Then, solder these two wires to the corresponding wires of the ribbon cable. Finally, secure the soldering joint you've just made with electrical tape.
Consider other 5V and ground pins on the board, like pin 2 for 5V, pin 9 for ground.
If all the V+/ground pins are used up, you may try to extend the pins. There are multiple ways. One of the simplest way is to connect the pin to a breadboard, such that you will have a few extra holes to connect to the same pin.
Beware not to connect too many devices. You may overload the Pi.