I fired up the heating system for the first time this year. All went well except that I noticed a humming sound coming from the A/C unit. I think the A/C blower fan is used to mix the air up when heat from the furnace is called for. Am I correct? The only change I made recently is the addition of a hard start cap to the A/C unit on the roof, but I don't think that could be connected to my hum issue.
Anyone have any ideas?
Michael & Tina
2016 Ford F-250 Lariat - 6.7L Powerstroke Diesel
2013 Kodiak 279RBSL