disconnect thermostat disconnected completely. if the two wires are
touched together, your system should operate normally calling for heat.
if you separate the wires, the system should stop calling for heat.
looks like you're spending too much time on the wire colors. if room is
cold and RH closes across C as tested with the thermostat calling for
heat with your ohmmeter, you should also see that circuit open when the
thermostat is warm.
call that toll free service number in the morning.