Standard Gauge Cluster Ammeter to Volt Meter conversion video

[JunkYardFind]

Finally finished the video that shows my Ammeter conversion to a Volt meter! It's pretty cool, the conversion turned out great! Check it out here on our JunkYard TV YouTube channel .... https://www.youtube.com/watch?v=puh8uICM_n0

[1972V21Cuda]

Cool. Though, I've never seen a Mopar have a problem with it?🙏

[72RoadRunnerGTX]

Nicely produced video but there are some points of contention here. I fear you are only perpetuating the "Ticking Time Bomb" Mopar ammeter myth. I see a perfectly good ammeter being cannibalized for an instrument providing far less useful information about charging system real time health. Not seeing any signs of any heat damage to the main ammeter bus, connection studs or insulators from loose or poor connections. All of the vehicle loads-alternator output does NOT flow through the ammeter as originally designed, only the battery charging/discharging current should be registered. With a fully charged healthy battery, heathy charging system, no added aftermarket loads connected directly to the battery, there will be little to zero current flowing through the ammeter and related connections. Ammeters don't cause problems, poor/loose connections, over tightened stud nuts, excessive moisture exposure and general lack of understanding of the function of the ammeter cause problems at the ammeter connections.



A lot of folks like to refer to the "Mad Electrical article" when doing or promoting an ammeter by-pass, voltmeter conversion. I would suggest another read through, note it was specially addressing the late seventies Dodge truck "plastic" ammeter melting issue. The passenger car ammeters from the sixties and seventies a not constructed with plastic framing, they will handle a great deal of current with clean connections and a little care. While some of their opening assertions are flat out wrong, there are other "by-pass" suggestions in the article there I agree with, bulkhead Packard connectors in the charging circuit for example. Address the Molex connections at the ignition switch as well. In my experience, do that before by-passing a perfectly good ammeter.

[70rag383]

Nice instructional video.

You make a very good point @72RoadRunnerGTX. There are potentially multiple points of failure with this system which when addressed properly will mitigate any issues you might have with the ammeter. For example my problem was with the bulkhead connection and the crappy packard connectors. I experienced this failure with a brand new wiring harness/bulkhead connector (5,000 miles).

[JunkYardFind]

@70rag383
Did you have the Ammeter bypass in place before this failure? What caused it?
I would like to avoid this (obviously) as I just replaced all the bulkhead wiring. I have the bypass in place along with the headlight relays.

[70rag383]

@70rag383
Did you have the Ammeter bypass in place before this failure? What caused it?
I would like to avoid this (obviously) as I just replaced all the bulkhead wiring. I have the bypass in place along with the headlight relays.

I did not have the ammeter bypass in place before the failure. It was caused by too much resistance in the bulkhead connector due to poor connections in the bulkhead. I was out driving around when the car just all of a sudden died. no power anywhere. I checked under the hood and the black wire from the alt to the bulkhead and the red wire from the bulkhead to the starter relay were burning hot.  the bulkhead connector for the black wire was completely fried as you can see from the photo. So I ran the bypass to the alt and also bypassed the bulkhead connector for both the black and red wire as per the instructions in the Mad Electrical article. Problem solved.  I did the headlight relays too.  It's good you have done the same.  If you're still going through the bulkhead just check the connections, make sure they are are not corroded and coat them with some dielectric grease. BTW, I learned to do all of this with help from the guys on this site. This place is amazing!

[72RoadRunnerGTX]

 To be clear, the use of Packard connectors in the charging system output, at the bulkhead connection is by far THE weakest link in the original design and has been since day one, not the ammeter connections. They failed quite commonly very early on. The factory by-passed them altogether on there Taxi and fleet production running 65amp alternators. There were even c-body factory recalls installing a parallel wire run, alternator stud to fuse panel.
Note, technically this factory recall "paralleled" the black alternator output Packard connection in the bulkhead connection, reducing the current flow though it without changing the ammeter function.
Before anything else, by-pass the charging circuit Packard connectors in the bulkhead.
Below is the fleet bulkhead full by-pass.

[Rbob]

@72RoadRunnerGTX Thank you for this info, I was just about to cannibalize my ammeter gauge, great info!

Is there any reason to run a 8 gauge wire to the starter relay as suggested (in other posts) or just run a parallel wire from alternator to the ammeter and/or fuse panel ?

Sorry, this may be off topic but related like a redheaded step-child.

[72RoadRunnerGTX]

Of the two charging system Packard connections in the bulkhead, the alternator to splice 1 to ammeter run (12 ga black wire) handles more current, battery charging circuit plus all vehicle loads, and is likely to fail first. I prefer to rebuild harnesses, remove the 12ga wires, replace with with 8 ga, bypass the bulkhead altogether, straight to the ammeter. Likewise, 8 ga to the fusible link. Short of that full harness rebuilds, running 12 or 10 ga parallel runs around the bulkhead connectors will help a lot to reduce current flow across the Packard connectors. For parallel runs with stock loads, on the ammeter to starter relay run, careful not to by-pass the fusible link.
On the old C-body recall mentioned, the supplied factory parallel wire included connections designed to go onto the alternator stud on one end and a female spade terminal to fit onto the "Batt" male spade at the bottom of the fuse box. Only reason for that was install time, it only paid something like .3 hours as I recall, most of my installs took place wherever I found them parked. I'd go to the ammeter stud however on these cars, drop the radio, pretty good access to the ammeter studs. 

[Rbob]

@72RoadRunnerGTX

Thank you for the info, it will help me a bunch.   

I have a new harness and I think I can use the smaller 12g wire to pull the 8 gauge wire into/thru the harness and bypass the bulkhead connector as suggested, that's my plan.

[Rbob]

@72RoadRunnerGTX

You stated: "I prefer to rebuild harnesses, remove the 12ga wires, replace with with 8 ga, bypass the bulkhead altogether, straight to the ammeter."

What do you do with splice 1 when replacing with above 8ga wire?

"alternator to splice 1 to ammeter run (12 ga black wire) handles more current"

Sorry for the hijack..

[72RoadRunnerGTX]

For the dash side of the bulkhead, assuming the dash harness is in good shape, simply reconnect the black original ammeter lead to the alternator side of the ammeter, this will feed splice 1. The splice 1 to bulkhead black 12 ga can be left as is or removed from the bulkhead and doubled back to ammeter for a second splice 1 feed, not really necessary for only stock loads running off the dash harness.   

Second shot is of my current E-body project, rallye cluster. Here I've also used the original red ammeter lead to power some blower motor by-pass relays. The other end of the red wire on this new M&H reproduction harness was removed from the bulkhead, fused and now supplies power to the relays. Again, the stock black ammeter lead feeds splice 1 for the stock loads.

[AKchallengerGuy]

Hello 72roadrunnergtx. I been watching your vids and reading what you have to say about this subject. I have a 70 challenger with new harness going in. Based on the second pic that is how I wire the bulkhead bypass to the ammeter and then send wires out to starter relay. And then black wire to  firewall mounted breaker then on to alternator correct? Also what is the gauge wire that you are using in the pic.

[72RoadRunnerGTX]

Missed this one, yea, that sounds about right. I normally will use 8ga wire for my by-passes. See post #8 on this thread for a more detailed description. Videos? YouTube? Yea, I've posted some videos going into more detail.