It's function is to keep the tension on your serpentine belt at the correct tightness. On most vehicles you will need to take the tension off in order to change the serpentine belt. On many vehicles...
Those who have love and affection remove others tension .
The main cause of tension is: when your angry you tense your muscle. Or wether you on a scary ride you get scared and tense your muscles then
stored energy with the ability to unleash that energy.
tenion pulley on serpentine belt will not release on 94 S-10 4 cy. with air