I sourced a new (usa made) Delco voltage regulator on Amazon. Part number C603Z.

https://www.amazon.com/gp/product/B000C9QI96/

I wanted to swap out the OEM one in my pickup because I'm registering around 14.6 volts average when the truck is running. My battery is reading about 13.6V when you shut things down and about 12.8V in the morning before you try to start it.

So I was hoping the Delco regulator would get me closer to about 13.8vdc.

The Delco arrived and upon hooking it up, I'm averaging 15.6vdc (verfied with a chinese cigarette plug meter and my fluke multi meter across the battery posts.)

Every once in a while you would even see 16.0 volts. My headlights already seem bright to me for being the originals from 1974. But with the Delco they were even brighter, like I had my high beams on.

So I swapped it out. Is there a reason the voltage would be high in either case? Does the metal case of the VR need to be attached to a good ground in order to work properly? Mine is bolted to the firewall with two non-rusty bolts.

Okeh...



I'm skeptical of that. I see where it says "USA" on the Amazon page, but I've also seen plenty of wrong product-origin callouts on Amazon.



Too high. Might not be a faulty regulator, though. The regulator isn't a mind reader; it can only react to what it sees on the wires connected to it. If there's high resistance in the voltage regulator wires, or an imperfect voltage regulator ground, the regulator will think line voltage is lower than it really is. It'll react by cranking up the voltage until it sees its setpoint voltage on the wires, but that'll mean higher-than-setpoint line voltage.



Did you ground the new regulator before running this test?



That problem will be solved for you soon enough; filament lifespan is exponential to the power -13 (negative thirteen) with voltage change. Filament rated 320 hours at 14 volts therefore can be expected to last 78 hours at 15.6 volts. And put better headlamps on your shopping list; the oldies gradually grow more and more and more useless before they finish burning out.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I tested the new rig with it bolted to the firewall. I'll check the cab to make sure it's grounded to the engine. I noticed a direct ground is recommended for people using this setup aftermarket. I may go that route if I can't get a good ground from the factory wiring/bolting to cab.





Here's the regulator box I got from Amazon. It's not marked USA anywhere on the unit itself. I picked up a NOS Borg Warner ignition module on ebay as well. Just trying to have quality spares around the garage if needed.

I went to an AC Delco seminar many years ago. Another attendee brought up the fact, to the instructor, about AC Delco outsourcing parts from China, and concerns about quality. He got the standard reply. "They are made to our spec". Yeah, right.

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Charrlie_S
65 Valiant 100 2dr post 170 turbo
66 Valiant Signet 225 nitrous
64 Valiant Signet
64 Valiant 4dr 170

Old Car Parts Northwest has shelves and shelves full of genuine Chrysler (and other brand) American-made voltage regulators, ignition modules, etc.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

Today I created an 8 gauge ground wire to bolt to the back of the alternator body and run up to the bolt on the voltage regulator. The end result is still higher voltage, if not even slightly higher?

I soldered the eyelet connectors to both ends of the wire and polished every surface I was connecting to ensure a solid grounding situation.





Here's a video of start-up showing the voltage levels.

https://youtu.be/DoBA0ZQtStQ

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63 Plymouth Valiant Wagon

See post № 2 in this thread.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I'll check resistance between the ends of both the red and yellow wires. Closest to zero ohms is best I assume?

I cleaned both the alternator and regulator terminals with DeOxit and both are good and tight.

If I find no resistance problems in the wiring, what other things should I consider? Can the alternator itself be bad for any reason where it ignores the regulator?

Well, yeah, but just checking resistance across the wire won't tell the whole story. An ohmmeter will pass very little current through the wire being tested. Suppose one of the wires has all but a few strands broken. Those few strands will still show near-zero resistance on most ohmmeters, but will pose enough resistance with the wire hooked up that there'll be voltage drop.



Not really, no, though it couldn't hurt to pull and inspect the brushes.

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

A few years ago I too had such a voltage regulator. My voltage read 15.1 volts at cruise (my gauge is very accurate- or was) and I didn't have time to fool with it because I was on the way to work. In no time my tail lights burned out, followed that night by the dash lights. My inexpensive and cheap Chinese made regulator surged to 37 volts before killing the ignition box. My cheapness cost me some gauges, bulbs, and ignition box.

Take that thing back and get a refund, then get a genuine Mopar regulator before you destroy something.

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If it was easy, everybody would be doing it.

Resistance from connector to connector on both the red and yellow wires fluctuates between 0.0 and 0.1 ohms. I know to never assume anything about wires I can't see inside the loom or insulation, but both wires have good insulation and look like they've had a pretty good life in terms of not being chewed up, bent up, etc.. The connectors are clean and shiny.

Is the next logical test to make my own 2 pin VR connector out of a new connector and wiring it straight to the alternator?



Resistance from ground on the alternator to ground on my firewall is 0.0 ohms.

The regulator used in the video I made is the OEM one. I experience the same results with the Delco unit.

Are there bench tests I can do with the multimeter on the regulators or the alternator?

Are the regulators with the potentiometer on the back worth investigating? I'd rather it just work as intended without the 'bandage' though.

Factory service manual should contain regulator test procedure. Did you pull and inspect alternator brushes?

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一期一会
Too many people who were born on third base actually believe they've hit a triple.

I haven't removed the brushes. I checked resistance from field to ground and both are infinite (open circuit) which I was told is correct. That was a test to make sure neither of the field coils are shorted out.

I don't possess a copy of the factory service manual, rather only the multi-year range Haynes which doesn't offer any help that way. The only service my manual shows is how to replace brushes in the nippon denso version of the alternator. I have a regular Chrysler one.

You have a shiner (exposed copper) on the yellow field wire at the alternator.

I like your ground wire. Hopefully the battery negative cable lands on the block as intended.

I know you said in the video that your plug-in volt meter was verified against a multi-meter, but you didn't show the meter or say what kind/brand.

The only other thing that comes up for me, aside from the regulator itself, is the electrical path through the ignition switch to the regulator. If there is voltage drop in that circuit you'll see that voltage drop added to the regulator set point. Check the switched ignition power at the regulator and see how it compares to the voltage at the battery.

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Joshua