Aux heat toggling on & off

[Dave0256]

I have a trane heat pump with Aux & emergeny heat. I heard the thermo stat clicking on & off ( and the lights blinking a little when surge of Aux relay turned on & off) tried to turn off the thermostat( off mode) but it continued to turn on & off the Aux heat. Finally raised the temp setting well above the set point on thermstat Aux came on & stayed on. I thought the thermostat was the problem so ditched my mercury one & put in a programable one honeywell 7500. worked great for week ,then my wife sayed it started all over again while i was at work same symptons. any ideas what may be causing this problem *

[Dave0256]

I have not noticed any mice or rat problem inside the house. but on the outside unit the dog as been digging after some kind of varmit at the outside unit where the compressor is located. the thermostat wires go to the unit inside the basement, now i wonder if it could be a short causing the unit to go into defrost cycle. would that bring on the *

[aircooledtx]

**"Dave0256"-* have a trane heat pump with Aux & emergeny heat. I heard the thermo stat clicking on & off ( and the lights blinking a little when surge of Aux relay turned on & off) tried to turn off the thermostat( off mode) but it continued to turn on & off the Aux heat. Finally raised the temp setting well above the set point on thermstat Aux came on & stayed on. I thought the thermostat was the problem so ditched my mercury one & put in a programable one honeywell 7500. worked great for week ,then my wife sayed it started all over again while i was at work same symptons. any ideas what may be causing this problem **/-*


It's called defrost, you can not control the thermostat when it is in DEFROST>>>>