I am rebuilding a Dell Optiplex 960. It uses a heat sink shroud assembly with 2 fans, however there is only 1 CPU fan socket on the motherboard. To solve this I assembled a Y-cable and connected all the same color wires. The fans run fines and there is no problem with overload on the motherboard with this arrangement. However, the fans only run on hgh speed. I understand I can solve this by disconnecting the RPM lead from one of the fans, while leaving the other connected. Since the fans are 4-wire units (color coded red, yellow, black and blue) I would think the blue wire is the RPM lead. Is my thinking correct on this approach ? Any help would be appreciated.