voltage regulator issues

Wiring, lights, heater controls, anything electrical..
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Jim100
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voltage regulator issues

Post by Jim100 »

This is the electrical area so I can really step it up and ask my dumbest questions.
My voltage regulator has been failing . I don't know its going bad until my battery finally is dead and the truck then stalls usually far from home and out in the country at night by the weird old abandoned house.
What gauge could I install that would give me a heads up?
Any ideas on the voltage regulator?
Thanks
jim

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MadMC63
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Re: voltage regulator issues

Post by MadMC63 »

What year is the truck?
C8313 Voltage Regulator
https://www.youtube.com/watch?v=F04fkFc9SNI

MOPAR CHARGING SYSTEM PRE-1970

Diagram #1 shows the basics of the early alternator / voltage regulator design. There are 2 brushes in the alternator, each one has a field terminal, one is labeled "FLD", the other is labeled "GND". The GND brush is grounded with the brush mounting screw. The other brush is the (+) brush (or field) and attached to it is a green wire that routes over to the voltage regulator (which is behind or near the brake master cylinder). This green wire is connected at the voltage regulator at the "FLD" connection (with a screw). The other connection on the voltage regulator is a blue wire with a female plug end. This is the "IGN" Ignition side.
Basically, the Voltage Regulator completes the charging circuit and allows the alternator to charge the system. When a certain voltage is obtained, the regulator "opens" (or turns off) the circuit until the electrical system's voltage drops, then it completes the circuit again. The old voltage regulators are repairable and rebuild able. The 1969 Dodge Shop manual (available from a number of vendors) details how to do this. If you think your regulator is failing, open it up and clean the "points" with some emory paper (sometimes these points get corroded).

NOTE: in diagram #1, the FLD is generally green, and the IGN wire is Dark blue on stock wiring harnesses.
Diagram #1.gif
Diagram #1.gif (2.22 KiB) Viewed 1068 times

MOPAR CHARGING SYSTEM - 1970 AND LATER

In 1970 Mopar switched from an analog type voltage regulator to a transistorized regulator. The basic circuit, shown in Diagram #2, is completely different. Before the voltage regulator monitored the (+) ignition voltage and opened/closed the (+) field circuit as needed to maintain a steady voltage. The 1970 design, instead, monitored the (+) field voltage and open/closed the (-) ground field as needed to maintain a steady voltage. To identify the (+) field circuit and (-) field circuit terminals on the alternator, look at the back of the alternator and put the "BATT" terminal at the 12 o'clock position. The two "FLD" terminals would appear as though they were at approximately the 10 o'clock and 11 o'clock positions. The terminal at 10 o'clock would be the (-) field circuit and 11 o'clock would be the (+) field circuit.
Diagram #2.gif
Diagram #2.gif (5.32 KiB) Viewed 1066 times
PRE-1970 CHARGING SYSTEM CONVERSION TO TRANSISTOR VOLTAGE REGULATOR

There are a number of reasons one might want to upgrade a pre-1970 system to a post- 1970 transistorized voltage regulator. The list of reason include

Chrysler recommends you switch to a transistorized voltage regulator if you upgrade to an electronic ignition from a points style ignition.
If you have to buy a new voltage regulator, the difference in cost is only about $5-10 more for the transistorized unit. Not to mention, the quality of replacement early style voltage regulators is spotty.
The transistorized voltage regulator will have a longer life.
Diagram #3 below describes how to install a 70 and later voltage regulator on a pre-1970 Mopar.
Diagram #3.gif
Diagram #3.gif (8.3 KiB) Viewed 1066 times

Basically, a wire is added to the second field brush on the alternator. On the original alternator, this brush is grounded to the case of the alternator, so you'll need to change the alternator to a 1970 or newer style. The second field wire is connected to the outside plug on the newer voltage regulator (two plugs, one is in the middle, one is on the outside). The original field wire that ran to the "FLD" plug on the original voltage regulator (green wire) needs to be connected with the wire that ran to the "IGN" side of the original voltage regulator. This wire (both the old FLD and the old IGN) need to be connected to the center plug on the newer voltage regulator as well. One more important step is required, the new voltage regulator must have a good case ground (-) to its mounting surface. If there isn't a good ground to the new voltage regulator case, the charging system will not work.

If a wiring modification of this level is not something you wish to tackle, reproduction engine wire harnesses for pre-1970 Mopars can be purchased that incorporate the newer voltage regulator and electronic ignition wiring and connectors.
1971 Dodge D100
So what's wrong with setting beneath a single pull string incandescent light bulb writing angry letters?

Jim100
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Re: voltage regulator issues

Post by Jim100 »

Thanks! Good info . Mine is set up like the 2nd. Solid state. And it continues to ruin regulators.
jim

Jim100
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Re: voltage regulator issues

Post by Jim100 »

Could really bad battery terminal connections cause a voltage regulator to fail?
jim

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Conrad
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Re: voltage regulator issues

Post by Conrad »

Jim100 wrote:Thanks! Good info . Mine is set up like the 2nd. Solid state. And it continues to ruin regulators.
jim
You can buy a cheap harbor freight voltage tester that will test your battery and alternator output. I use mine all the time.

Make sure your alternator is grounded properly. I had problems like this on my Valiant and eventually gave up and bought a one wire powermaster alternator and happily ditched the regulator but you shouldn't have to do that if you have good constant grounds.

The complication/expense with the one wire is that you should run a fat charging cable down to your starter solenoid. And ideally protect the solenoid with a fuse.

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