I have a 98 chevy 1500, has a 105 amp alternator that is not doing the job now, I had it tested at different auto parts stores all say its not working. I have a snow plow mounted and only do a few driveways but push the switch to operate the plow and it uses a lot of power and that's typical it really never has worked well for the plow and I wonder if that has hod something to do with wearing out the alt . I added a second battery a couple years ago and doesn't seem to help much, I'm wondering if I can step up to a new alt with a higher output like say 130-140 amps if that would help and can I do that without changing other equipment on my truck? each parts store tells me a different story and I don't know who to believe? Any help I can get on this matter would be appreciated. Thanks.

S N

Switching to a higher output alternator, in conjunction with the added battery may just do what you need it to do.
If you really want to get innovative, you can track down an smaller diameter pulley for your alternator and change to a slightly shorter serp belt (one short enough to accommodate the pulley change) That will serve to speed up your alternator rotation and result in increased output. Note: this could also void your alternator warranty, too.

Plows do take a lot of power and this normal, did they say what is wrong with the alt. u can take it apart and check the brushes and reg and the dioes if u have a meter, the brushes could be wore out, just remember to mark the body of the alt when u take it apart. There is a hole in the brush holder u can put a pice of wire into it so u can put it back togeather, dit u check the blet for tightness, check the pulg on the regulater on the altenator,