belt

I have a 93 1/2 ton 1500 P/u it has 127,000 and the serpentine belt jumped the tensioner. what can be the possible cause of this? also the parts people tell me I need to find out what AMP the alternator is due to length of the belt. But I have no way of identifying this? it`s either 80/100/120 AMPs.Any help is greatly appreciated.

I have a 93 1/2 ton 1500 P/u it has 127,000 and the serpentine belt jumped the tensioner. what can be the possible cause of this? also the parts people tell me I need to find out what AMP the alternator is due to length of the belt. But I have no way of identifying this? it`s either 80/100/120 AMPs.Any help is greatly appreciated.

A weak tensioner or misaligned pulley can cause the belt to jump. The AMP should be stamped on the alternator. It is hard to see but it should be stamped on it. Use a rag to clean off the alt and you should be able to see it.

//2000CAYukon

You should know how to recognize the differents sign of a bad tensioner.
I thought mine was good when i replaced the belt about a year ago because
the pulley & travel seemed OK but last week it was separating from it's
fixed position so I replaced it. I went through 2 new ones right away &
thought I got bad parts but turned out the stretched belt was letting the new
tensioner go into a position that would blow the bearings in the pully right
away. For the benefit of anyone searching this theme, I would replace the
belt with the tensioner.

Also, my year truck had an issue with PS pump pully alignment. Mine
seemed OK as the shaft was flush with the pulley. You should check
the alignment & free flow of your pulleys & accessories. My AC cut off
switch was bad & my compressor was leaking & it was disengaging &
engaging frequently & abruptly it seemed to me.