No tank heater switch

[hawlguy]

bought used 2017 cardinal 3456 awhile back. Holding tanks/dump valves frozen. Have 20amp fuse installed for heat tanks in fuse panel, but can’t find a on/off switch anywhere? LCI panel has no controls for it. Is this automatic temp triggered system or am I just stupid?

 

[hawlguy]

bought used 2017 cardinal 3456 awhile back. Holding tanks/dump valves frozen. Have 20amp fuse installed for heat tanks in fuse panel, but can’t find a on/off switch anywhere? LCI panel has no controls for it. Is this automatic temp triggered system or am I just stupid?

PS….batteries show 13volts

 

[Rich W.]

should be a switch somewhere - might be labeled weird like “110v heat pads” or something equally vague.