HVAC Relays & Fan limit switch wiring. Part 1 of 2. - YouTube Click to view on Bing4:07Aug 05, 2011Furnace fan center troubleshoot - Duration: Troubleshooting Goodman Fan Relay & Electrical Disconnect - Duration: Blower / Heat Relay Interlock Wiring - Duration: 10:53.Author: rdelosreyes67Views: 40K furnace fan relay wiring – chantalbauwens The relay in the above control diagram controls a blower motor as shown. . If you have a gas furnace or other type of heating system the fan will be controlled . 08/09/2017 - While I am experienced at wiring in general, I am a. . which has a 24 V coil and simple Open/Close circuit relay and hooking the fan to the relay is not a problem. .