Alternator and Battery Question 1988 Corvette C4


Asked by May 25, 2017 at 03:13 PM about the 1988 Chevrolet Corvette Coupe RWD

Question type: Maintenance & Repair

I just changed out my battery, and it reads 12 Volts.   I just changed out my
alternator to an AC Delco.  Now upon driving, on the dash display the volts
read  11.7 and holding when I drive, I put on the air conditioner and it goes
down to 11.6, when I put on the headlights it goes down to 11.4 - 11.3, but
then shoots back up to 11.7 and holds... Had the new battery and new
remanufactured alternator check out and it passed at AutoZone (both out of
the car) -- isn't the voltage supposed to read out at least 12 to 13 to 14 volts?    
What could be drawing the power?  And if I drive more than 20 minutes, the
voltage keeps going down, dash dims, put the foot on the brake and the
dash board dims in and out and now we're in 10's as far as volts.   Please

1 Answer


Definitely sounds like a bad alternator. But check your connections and grounds at the alternator. Be sure the alternator drive belt isn't slipping. If it's a "V" type belt there should be 1/2 inch deflection midway between the alternator pulley and the other pulley the belt goes onto. Check your battery cable connections as well, at both ends. Be sure everything is clean and tight. Did they check the alternator for amperage as well as voltage output? HTH. -Jim

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