hey everyone im new here i got a 1999 gmc sierra 5.3 v8

my issue is that when the truck is running my volt meter bounces, my head lights and dash lights flickers a little,

i got the battery and alternator tested and all is well with them!

any ideas!

 

sounds to me like the alternator... it may be charging but sounds as though the diode ripple is messed up, which would be the alternator... as a mazda mechanic also ive seen that before on the mazdas quite a bit...

 

hmmmm... time to price out a alternator lol!!

 

just found out it might be my dash board.. like the clusters! .. umm and it is drawing alot of power!

 

picked up a new alternator... still doing the same thing!! gunna pick up a new speed cluster today to see if thats the issue

 

was the speed clusters!!