Cooling System R2.8 CM2220 R101B Page 1-18 Section 1 - Installation by Subsystem Figure 2 - Electric Cooling Fan NOTE: The fan signal and return wires are meant to power a relay, and not the fan directly. Follow the manufacture recommendation for the electric fan installation wiring and the size of the control relay. Figure 3 is a typical fan relay with no current flowing to pin 33, fan OFF. See the R2.8 CM2220 R101B Wiring Diagram, Bulletin 5467560, on QuickServe™ Online. To buy Cummins Parts and Service Manuals, Training Guides, or Tools go to our website at https://store.cummins.com