TECH TIP FOR DECEMBER, 1995

CHRISTMAS HOURS : WITH CHRISTMAS FALLING ON A MONDAY AND THE NEXT DAY BEING A HOLIDAY TOO, THE TEMPTATION IS TO CLOSE FOR THE WHOLE WEEK. BUT!! WE AREN'T DOING THAT, WE WILL CLOSE AT 5:00pm ON DECEMBER 22 AND RE©OPEN AT 8:00am ON DECEMBER 27. AT NEW YEARS WE WILL FOLLOW THE SAME PATTERN, AND WILL CLOSE AT 5:00pm, DECEMBER 29 AND REOPEN AT 8:00am ON JANUARY 2.1996.

WE HOPE THAT EVERYONE ONE HAS A HAPPY AND SAFE HOLIDAY SEASON AND A PROSPEROUS NEW YEAR.

A FRIEND OF MINE HAS BEEN PUTTING WIRING INFORMATION IN HIS RECENT TECH TIPS, AND IT SEEMED LIKE A GOOD THING TO COPY, SO HERE GOES:

LET'S START WITH CHRYSLER PRODUCTS - EXCEPT FOR 1984/85 WHEN CHRYSLER USED AN INTERNALLY REGULATED BOSCH ALTERNATOR ON SOME MODELS, AND CARS WHICH ARE NOT MANUFACTURED BY CHRYSLER, BUT ARE SOLD UNDER THEIR VARIOUS BRAND NAMES, CHRYSLER PRODUCTS HAVE BEEN AND CONTINUE TO BE EXTERNALLY REGULATED.

BEFORE 1984, THE REGULATOR WAS THAT 3" X 2" BOX, USUALLY FASTENED TO THE FIREWALL, WITH TWO WIRE RUNNING TO IT. THE PLUG ON THE REGULATOR WAS A TRIANGLE POINTING DOWN THE LENGTH. THE BOTTOM PIN IS "IGNITION" AND THE REMAINING WIRE IS "FIELD". THE CASE IS GROUNDED TO THE FIREWALL.

A VERY SIMPLE WAY TO DESCRIBE HOW THE SYSTEM WORKS IS: WITH THE KEY IN THE "ON" POSITION, FULL VOLTAGE IS FED DOWN A LEAD TO ONE OF THE BRUSHES ON THE ALTERNATOR, IT GOES THROUGH THE ROTOR AND LEAVES VIA THE OTHER BRUSH, TRAVELLING UP THE ATTACHED LEAD TO THE "FIELD" TERMINAL OF THE REGULATOR. THE REGULATOR COMPARES WHAT IT SEES ON THE LEAD FROM THE ALTERNATOR TO WHAT IT SEES ON THE "IGNITION" TERMINAL AND CONTROLS THE OUTPUT OF THE ALTERNATOR BY VARYING THE AMOUNT OF CURRENT IT ALLOWS TO GO TO GROUND. THIS IS KNOWN AS AN "A" CIRCUIT SYSTEM BECAUSE THE CONTROL OF THE ROTOR FIELD IS AFTER IT PASSES THROUGH THE ROTOR.

SINCE THE REGULATOR USES ITS CASE WHERE IT FASTENS TO THE FIRE WALL AS A GROUND A HUGE NUMBER OF CHRYSLER REGULATORS HAVE BEEN THROWN OUT BECAUSE THE INSTALLATION OF A NEW REGULATOR HAS CORRECTED THE CHARGING PROBLEM. IN FACT WHAT PROBABLY HAPPENED, WAS THAT THE INSTALLATION OF THE NEW REGULATOR CLEANED AND IMPROVED THE GROUND, WHICH WAS ALL THAT WAS WRONG IN THE FIRST PLACE.

OBVIOUSLY, IF BECAUSE OF CORROSION OR A FRAYED WIRE, THERE IS INSUFFICIENT CURRENT GETTING TO THE ROTOR THE REGULATOR WILL NOT KNOW WHAT IS HAPPENING AND MAY THINK THAT THE BATTERY IS VERY LOW, KEEPING THE SYSTEM TURNED ON, AS MUCH AS POSSIBLE, ON A FULL TIME BASIS. SIMILARLY, IF THE LEAD FROM THE ALTERNATOR TO THE REGULATOR BECOMES GROUNDED, THE ALTERNATOR WILL "FULL FIELD" AND IN VERY SHORT ORDER COOK THE BATTERY, AND DAMAGE OTHER COMPONENTS.

IF FACT I KNOW OF ONE INSTANCE WHERE THERE WAS A SHORT AND BECAUSE THERE IS NO OVER VOLTAGE INDICATOR, THE DRIVER OPERATED THE VEHICLE UNTIL EVERY ELECTRONIC COMPONENT, THE BATTERY, HIS TWO WAY RADIO AND SOME OF THE WIRING CAUGHT FIRE OR WERE MELTED DOWN. THIS WAS OF COURSE THE REGULATOR'S FAULT!

AS "FULL FIELDING" THE CHRYSLER SYSTEM REQUIRES ONLY THAT YOU GROUND THE BRUSH THAT THE LEAD GOING FROM THE ALTERNATOR TO THE REGULATOR IS CONNECTED TO, THERE IS A TEMPTATION TO DO IT TO FIND OUT IF THE PROBLEM IS WIRING OR THE ALTERNATOR, BUT I SUGGEST THAT YOU USE SOME DISCRETION HERE,BECAUSE.... SINCE 1984 CHRYSLER HAS MOUNTED THE REGULATOR INSIDE THE COMPUTER, AND SINCE COMPUTERS LIKE HIGH VOLTAGE SPIKES AS MUCH AS YOU LIKE A POKE IN THE EYE WITH A SHORT SHARP STICK, AND SINCE THE COLLAPSING FIELD OF AN ALTERNATOR CAN GENERATE A SPIKE OF AS MUCH AS 240 volts......... IT CAN BE DONE BUT IT CAN GET REAL EXPENSIVE, REAL FAST!

A QUICK CHECK OF THE CHRYSLER SYSTEM; WITH THE KEY ON, DO YOU AVE VOLTAGE AT ONE OF THE BRUSHES OF THE ALTERNATOR, DOES IT APPEAR AT THE OTHER ALTERNATOR BRUSH TERMINAL, DOES IT APPEAR AT THE REGULATOR, DO YOU HAVE MAIN BATTERY AT THE OUTPUT TERMINAL OF THE ALTERNATOR, ARE BOTH THE ALTERNATOR AND THE REGULATOR GROUNDED? IF ALL QUESTIONS ARE ANSWERED YES, THEN EITHER THE ALTERNATOR OR REGULATOR IS BAD.

IF YOU DISCONNECT THE ALTERNATOR FROM THE VEHICLE WIRING AND CONNECT IT TO AN EXTERNAL BATTERY WITH BOOSTER CABLES AND JUMPER WIRES, YOU CAN SAFELY "FULL FIELD" THE ALTERNATOR AND DETERMINE WHICH ONE IS BAD. IF THAT IS NOT CONVENIENT OR NOT EASILY ACCOMPLISHED, THEN BRING ME THE ALTERNATOR, AND A QUICK BENCH TEST WILL TELL WHICH IS BAD. SEEMS LIKE A LOT OF WORK, BUT I'LL BET IT'S CHEAPER THAN A COMPUTER.

NEXT MONTH WE WILL COVER THE DELCO/GM SYSTEM. AGAIN HAVE A HAPPYAND SAFE HOLIDAY SEASON.