Bean shows a sign of life (5)
I believe the answer is:
pulse
This clue is a double definition.
'bean' is the first definition.
(I know that bean can be written as pulse)
'a sign of life' is the second definition.
(a person's pulse)
'shows' acts as a link.
(Other definitions for pulse that I've seen before include "Series of rhythmic beats" , "It beats - peas and beans" , "often sought medically?" , "Lentil, bean, seeds" , "Vibration" .)