On Isuzus the PCM monitors the alternator output. If there is a problem it will cut out all "non essential" equipment. The blower, rear defroster, etc. are considered non essential. That way it will allow as much power as possible to try and get you to where it can be fixed.

--Dave

1999 Rodeo LS 3.2 4x4 5 Speed
32x11.50-15 BFG T/A KO on US Wheel 94 series
3" Lift - Rancho 9000x
Rear No-Slip Locker
Flowmaster 50 series SUV 2.25"

There is a very fine line between "hobby" and "mental illness." - Dave Barry