All ActivityMost RecentMost LikesSolutionsRe: heater fan on today the switch was set to ACsorry its been awhile since ive been back on, I had only 2 days off last month and 10 hour days. what I found out I had an invasion of ants and they had gotten in my mother board controls and they caused my fans to kick on. one can of ant spray and a week with the fuse out cured my problem. Thanks for all the help.heater fan on today the switch was set to ACI came in from work today my heater fan was running, the fan was running outside thru the heater exchanger but it had no heat in it and the heater fan inside was blowing. my switch was set to AC, I went thru the settings on the wall switch and it didn't shut off. I ended up taking out the fuse to get it to stop. 2016 prime time tracer 2940 rks. Any ideas on what it could be before I call the dealer. I am living in it while im out of town.