alternator

[Bbob2]

Does anyone know why the needle for the alt fluctuates from 14 volts at idle down to about12.5 while driving? Normally when shifting into a gear.

[rodeo02]

Prolly a bad voltage regulator in the alternator. Sometimes they'll stay steady if you keep a load on'em like keeping the headlights on.
G/luck
Joel

[Canucklehead]

Don't know what year you have but...

From page 2-8 of the 1997 Rodeo Owner's Manual:
"When the accelerator pedal is pressed, when driving or with the engine idling, the voltmeter will drop into the low voltage range. This results from a changeover in alternator voltage control designed for fuel economy improvement. However, the voltmeter needle will not drop if the head lights are turned on or if the engine coolant temperature remains low."