Decided to do some more research before dropping cash on a new alternator.

Testing at the back of the alternator gave me 14v. Testing at battery reads 13.7

With lights and both AC running on high ug reads 13.5. Battery was 13.6 alternator 13.9

Further testing with 1 lead on alternator positive terminal and other on battery positive showed .3 volts.

This is leading me to believe the alternator is fine and I'm loosing voltage in the cable

Does my reasoning seem correct?

 

Yeah.. cables corrode inside and that'll do it.

I replaced my negative cable with a 2 gauge wire from Autozone and a set of marine clamps, getting better voltage every since that, and no more M+S lights on startup. I ran one wire to the block next to the battery, and another to the alternator bracket. IMO a better setup than factory, less resistance being it is two cables instead of one to multiple locations.

I'm planning to do the positive cable next.

 

Not getting m s lights but my transmission does NOT like when the voltage drops below 13.7

Wondering if the whole cable is bad or just the end

 

Even if it's just the end, replace the whole cable, it's cheap and once corrosion gets under the insulation you can't stop it from spreading.

I always use marine tinned wire and marine connections with adhesive lined heat shrink covering the lug to wire connection

 

Going to replace both positive cables. Can anyone recommend what length for each?