Chevrolet Repair: Electrical problem, negative battery cable, 1988 chevy 1500

Question
Tom,I have an electrical problem with my old plow truck. It is a 1988 Chevy 1500 series. I have put in a new battery and have replaced the old cables, but the battery will still not hold a charge. The alternator gages indicates that it is charging when it is running. Does this old truck have a voltage regulator and could it be bad?

Answer
HI CHUCK,NO THIS TRUCK DOES NOT HAVE A EXTERNAL REGULATOR. IT IS INTERNAL OF THE ALT. DO YOU HAVE A VOLT METER? IF SO HOOK IT UP THE BATTERY,TURN THE LIGHTS ON ,WE NEED TO SEE 13.8 TO 14.5 VOLTS WHEN RUNNING IF SO, WE KNOW THE ALT IS GOOD. [DO NOT RELY ON THE DASH GAUGE.] IF NOT TAKE IT BACK TO REBUILT SHOP. I HAVE SEEN ALOT OF FAULTY ALTERNATORS.. BUT LETS SAY THE ALT IS CHARGING TO SPECS. THAT LEAVES 2 CAUSES. FAULTY BATTERY. BEING NEW, THIS IS MORE THEN LIKELY NOT THE CAUSE..LAST IS A DRAW WHEN THE KEY IS OFF. [PARASITIC DRAW] ON THIS YEAR TRUCK THE BEST WAY TO CK FOR A SHORT OR DRAIN IS GET YOURSELF A TEST LIGHT,REMOVE THE NEGATIVE BATTERY CABLE, PUT ONE OF THE LEADS FROM THE TEST LIGHT ON THE NEG CABLE ITSELF AND TAKE THE OTHER LEAD FROM THE TEST LIGHT AND PUT IT ON THE NEG POST OF THE BATTERY.IF THE LIGHT LIGHTS YOU HAVE A DRAIN...MAKE SURE THE KEY IS OUT OF THE IGNITION AND ALL LIGHTS ARE OFF WHEN DOING THIS TEST..TO CK TO SEE IF THE TEST LIGHT IS MAKING GOOD CONNECTION TURN ON THE PARKING LIGHTS, THE TEST LIGHT SHOULD LIGHT LIKE THIS...IF IT LIGHTS THE CONNECTION IS GOOD,TURN THE LIGHTS BACK OFF AND MAKE SURE THE TEST LIGHT HAS NO LIGHT AT ALL. IF SO,REMOVE ONE FUSE AT A TIME TILL THE LIGHT ON THE TEST LIGHT GOES OUT. WHEN IT GOES OUT YOU FOUND THE CIRCUIT WITH THE DRAIN.[MAKE SURE YOUR DOORS ARE CLOSED WHEN TEST FOR A DRAIN] NOW YOU WILL NEED TO CK THAT CIRCUIT VERY CAREFULLY TO SEE WHAT IS CAUSING IT,COMMON PROBLEMS ARE THE COURTESY CIRCUIT..IF THIS DOES NOT SOUND LIKE SOMETHING YOU WOULD LIKE TO DO, REMOVE POS OR NEG CABLE FROM THE BATTERY TONIGHT AND SEE IF THE TRUCK STARTS UP THE NEXT MORNING. IF SO YOU HAVE A SHORT. IF YOU DO NOT WANT TO LOCATE THE SHORT THEY MAKE A KILL SWITCH TO PUT AT THE BATTERY CABLE BEFORE HOOKING UP TO THE BATTERY ITSELF. YOU TURN THIS SWITCH AND IT REMOVES THE POWER GOING TO THE TRUCK. THEY ARE VERY CHEAP AND SOLD AT ALL PART STORES. I HOPE THIS HELPS YOU,IF YOU NEED MORE INFO GET BACK TO ME. PLEASE WHEN YOU LEAVE THIS SITE WOULD YOU RATE MY ANSWER. THANK,YOU TOM