Systems are provided for measuring temperature in a semiconductor processing chamber. Embodiments provide a multi-junction thermocouple comprising a first junction and a second junction positioned to measure temperature at substantially the same portion of a substrate. A controller may detect failures in the first junction, the second junction, a first wire pair extending from the first junction, or a second wire pair extending from the second junction. The controller desirably responds to a detected failure of the first junction or first wire pair by selecting the second junction and second wire pair. Conversely, the controller desirably responds to a detected failure of the second junction or second wire pair by selecting the first junction and first wire pair. Systems taught herein may permit accurate and substantially uninterrupted temperature measurement despite failure of a junction or wire pair in a thermocouple.