83 Wanderlodge 40 PT A/C & electric heat relays

[wellsd62]

Who Knows?
In wardrobe closet, under breaker panel, metal enclosure with three
relays that switch power for cental air and or electric heat. Where is
the 12v switched for these relays? Appears that 12v power is hot to all
three relays and the ground is switched. Two of the relays are working
normally the other pulls in if I ground it. Are these relays only
switched at the master power switch under the dash, or are there other
switches or controls I'm not seeing. The one causing the problem is for
the bedroom A/C and heat. WHO KNOWS???????????????
Thanks Dan