Let me know if you find the problem. I went on long drive yesterday, and 1 hour from home at night, the volt meter was reading very low, I guessed it was the alternator regulator failure, the suburban had that twice in 10,000 miles. I stopped to check the belt, nearly removed the end of of my finger by touching the alternator fan which looked stopped, then on leaving the gauge showed normal voltage.
Grant H.
1995 6.5 turbo GMC K2500 extra cab 4x4 pickup, PMD under bumper, mechanical wastegate, 228,000 miles, rebuilt engine, 4.10 diff, 16 mpg
1994 6.5 turbo GMC K2500 4x4 suburban #9 resistor, PMD in the bumper, mechanical waste gate, 226,000 miles, 3.73 diff, 16 mpg
1982 4x4 shortbed 6.2 Chev 260,000 miles untouched motor 17 MPG 4.27 diff. Best thing I ever owned, since 1992.