Factory ammeter

[Mattax]

I like the sounds of that. I always hated how dim my headlights were

Not sure what year you have but the 6014 lamps that came in somewhere after '73 model year were brighter but drew more current.
So this put a greater load on the a-body headlight systems which used 18 ga wires to the lamps, and light switches with 15 amp breakers, etc.
Its also a lot conenctions and fairly distance for the electricity to flow.

Rusty explained the work around uses relays.
How this helps is the power for the lamps can flow from the alternator directly to the relay to the lamps.
Using larger wire sizes, shorter distances, and few connections results in less resistance to current flow and higher voltage at the lamps.
So even without changing lamps, they will work better.
Bonus is that the alternator's output wire no longer carries that power. So when you're driving at night in a cold rain with wipers, lights, and heater going, that's something around 10 amps less current going through the bulkhead connector. That's significant.

As far as alternator output, do a search here. The way to really know is to load it at increasing rpms. All of them have more capacity as rpm goes up. What is usually most important is whether it has enough power to run the car and most accessories while driving. If you stuck in traffic or other idle situations, then power at idle rpms can be of imprtance too.

 

[Dartfreak75]

Not sure what year you have but the 6014 lamps that came in somewhere after '73 model year were brighter but drew more current.
So this put a greater load on the a-body headlight systems which used 18 ga wires to the lamps, and light switches with 15 amp breakers, etc.
Its also a lot conenctions and fairly distance for the electricity to flow.

Rusty explained the work around uses relays.
How this helps is the power for the lamps can flow from the alternator directly to the relay to the lamps.
Using larger wire sizes, shorter distances, and few connections results in less resistance to current flow and higher voltage at the lamps.
So even without changing lamps, they will work better.
Bonus is that the alternator's output wire no longer carries that power. So when you're driving at night in a cold rain with wipers, lights, and heater going, that's something around 10 amps less current going through the bulkhead connector. That's significant.

As far as alternator output, do a search here. The way to really know is to load it at increasing rpms. All of them have more capacity as rpm goes up. What is usually most important is whether it has enough power to run the car and most accessories while driving. If you stuck in traffic or other idle situations, then power at idle rpms can be of imprtance too.

Mine is a 75. This is good info thank you all.

 

[crackedback]

I've built kits for factory hemi E bodies, and those guys are generally "picky" about what they put on their cars.

If you are building a 100 point show car... keep it all factory. If not, JMO, use products that improve performance in many areas that can be easily hidden. If you have a battery tray in an A body, the relays hide underneath and the wiring hides extremely easily within the OEM harness and tabs.

 

[Dartfreak75]

I've built kits for factory hemi E bodies, and those guys are generally "picky" about what they put on their cars.

If you are building a 100 point show car... keep it all factory. If not, JMO, use products that improve performance in many areas that can be easily hidden. If you have a battery tray in an A body, the relays hide underneath and the wiring hides extremely easily within the OEM harness and tabs.

Thanks its not a show car I just want things to be left as original as possible for simplicity reasons lol tbh I suck at wiring and electrical and I dont want to rewire or modify anything that I dont have to hence wanting to keep the factory ammeter in working conditions. I want all my gauges to work and I want to be able to keep an eye on the charging system too. I don't want the appearance of the interior to remain factory looking so I don't want to cut any holes in my cluster for a aftermarket volt gauge.

 

[Dartfreak75]

I'm still running all my factory gauges with no issues for 48 years. Keep it factory, it's looks better in my opinion.

Yea I agree I like the look of a original interior

 

[crackedback]

Thanks its not a show car I just want things to be left as original as possible for simplicity reasons lol tbh I suck at wiring and electrical and I dont want to rewire or modify anything that I dont have to hence wanting to keep the factory ammeter in working conditions. I want all my gauges to work and I want to be able to keep an eye on the charging system too. I don't want the appearance of the interior to remain factory looking so I don't want to cut any holes in my cluster for a aftermarket volt gauge.

My stuff is all plug and play... no cutting rewiring, add two ring terminals at alternator, two grounds for headlights and the rest plugs in to factory ends... simple and easy to remove and transfer to a new car if you want to keep it.

Just know the limitations of the OEM system because it not good, IMO. Horrible design and execution.

 

[RustyRatRod]

Not sure what year you have but the 6014 lamps that came in somewhere after '73 model year were brighter but drew more current.
So this put a greater load on the a-body headlight systems which used 18 ga wires to the lamps, and light switches with 15 amp breakers, etc.
Its also a lot conenctions and fairly distance for the electricity to flow.

Rusty explained the work around uses relays.
How this helps is the power for the lamps can flow from the alternator directly to the relay to the lamps.
Using larger wire sizes, shorter distances, and few connections results in less resistance to current flow and higher voltage at the lamps.
So even without changing lamps, they will work better.
Bonus is that the alternator's output wire no longer carries that power. So when you're driving at night in a cold rain with wipers, lights, and heater going, that's something around 10 amps less current going through the bulkhead connector. That's significant.

As far as alternator output, do a search here. The way to really know is to load it at increasing rpms. All of them have more capacity as rpm goes up. What is usually most important is whether it has enough power to run the car and most accessories while driving. If you stuck in traffic or other idle situations, then power at idle rpms can be of imprtance too.

Oh that ain't how it works at all. It just makes the headlights bright as crap. lol

 

[str12-340]

Even Ma Mopar identified this problem back in the day. In fleet vehicles (cop cars and taxis) they bypassed the bulkhead connector with the two wires that go to the ammeter and ran them through a grommet in the firewall. you can do the same, or if you don't want it to look altered, gut your bulkhead connector where those two wires pass through and run the wires all the way through with a better connector under the dash. If you use a connector that you can pull through the bulkhead connector, you can still disconnect the wires under the dash and then disconnect the bulkhead connector and pull those wires out on the engine bay side when needed.

If you have access to an electrical rebuild shop, they can spin the alternator and measure the output. Factory Service manual (usually available on line) will tell you what the original alternators put out for standard, with AC and fleet vehicles. I'm a big fan of ammeters - I'd rather know if the system was overcharging or not charging before a voltmeter tells me it's too late - both a voltmeter and an ammeter is ideal.

 

[Dartfreak75]

If I wanted to run a separate voltage gauge how would wire that in? I kinda like the cig light adapter idea I have a bluetooth in my edd that has that feature.

 

[RedFish]

The 75 model doesn't have the same amp gauge with all the load routed through it. 75 model has a remote shunt mounted somewhere outside the firewall ( I forget exactly where ). Your amp gauge is connected to the printed circuit board like all the other gauges. That is less conductor than the typical volt gauge has. So all the amp gauge failure stuff you read on line does not apply to your car.
The later models have power distribution through multiple fusible links too. Earlier models have lights and everything else routed through 1 fusible link. So you already have a separate and more direct supply to your headlights. Relays would take the current load off the headlight switch but that defeats the purpose of the cycling circuit breaker protection inside that switch. Its usually the dimmer rheostat on them that fails first anyway.

 

[67Dart273]

The 75 model doesn't have the same amp gauge with all the load routed through it. 75 model has a remote shunt mounted somewhere outside the firewall ( I forget exactly where ). Your amp gauge is connected to the printed circuit board like all the other gauges. .

Pretty sure all external shunt setups simply use the harness itself as the shunt. I have actually lengthened a harness in a Ferd pu to get the ammeter to be a bit more sensitive. That is a failing of many models with that setup..........the thing is numb. My old Ranger, you could pull on the headlights, you had to 'stare intently' at the ammeter to see if it moved!!

 

[Mattax]

If I wanted to run a separate voltage gauge how would wire that in? I kinda like the cig light adapter idea I have a bluetooth in my edd that has that feature.

Wire the positive to the location you want to measure voltage, preferably a location that is disconnected with the key off.
There may be a terminal in the fusebox that's available on the 'accessory' feed. "Accessory" is everything not related to running the engine and is switched.
Sometimes there's an available connector or switched power terminal in other locations such as the wiper switch.
The cig lighter is certainly the easiest.

The last '75 I was looking at had the internally shunted ammeter and was wired like most standard option '72-74 as far as the main feeds went.
@zkx14 car and he checked whether it had the ammeter connections were through the grommets here
But if Redfish says shunted ammeters came in during '75, I wouldn't doubt that. So as far the wire paths go, see what is on your car and how it matches up.

 

[yellow rose]

Thanks its not a show car I just want things to be left as original as possible for simplicity reasons lol tbh I suck at wiring and electrical and I dont want to rewire or modify anything that I dont have to hence wanting to keep the factory ammeter in working conditions. I want all my gauges to work and I want to be able to keep an eye on the charging system too. I don't want the appearance of the interior to remain factory looking so I don't want to cut any holes in my cluster for a aftermarket volt gauge.

It’s almost impossible to be as wiring and electrically ignorant as I am.

I used Crackedback’s harness. It’s so simple I can do it. You can hide the wires and 99% of the lookie Lou’s will never see it.

The lights will be brighter. With new lamps, they will be as bright as any new car. Plus, it takes some of the load off the bulkhead connector.

There are before and after pictures of the 73 Duster I did. And the pictures do do it justice.

I too don’t want to change any more that I have to, but Crackedback’s harness is so easy to install, so easy to hid and works so dang good that when my junk goes back together next spring, I’m using it.


It’s THAT good.

 

[cudamark]

Also too, if you do decide to keep the factory amp gauge, remove the cluster and clean all of the connections GOOD. On mine, it is held in with little speed nuts. They also give it the electrical connection. I recently removed mine to repaint the plastic housing and put LEDs where the two instrument lights go. I noticed some white corrosion around the nuts that hold the amp gauge in, so I removed the gauge, cleaned everything up good and put it back together. Make sure the nuts are tight, but you don't have to be Superman. They were almost finger tight when I removed them, so it needed attention.

No way the ammeter should have a single set of speed nuts holding the gauge and wires. The factory used regular (and in most cases copper) threaded double nuts. One set of nuts held the gauge to the housing(with a special insulator washer underneath) and second set of nuts to hold the wires. As long as everything is clean and tightened properly, the system works just fine in a stock car. Now, you start adding accessories and upping the draw on the system, you'll need to make some mods.....one of which might be to bypass the ammeter. That would depend on the added load.

 

[Dartfreak75]

Wire the positive to the location you want to measure voltage, preferably a location that is disconnected with the key off.
There may be a terminal in the fusebox that's available on the 'accessory' feed. "Accessory" is everything not related to running the engine and is switched.
Sometimes there's an available connector or switched power terminal in other locations such as the wiper switch.
The cig lighter is certainly the easiest.

The last '75 I was looking at had the internally shunted ammeter and was wired like most standard option '72-74 as far as the main feeds went.
@zkx14 car and he checked whether it had the ammeter connections were through the grommets here
But if Redfish says shunted ammeters came in during '75, I wouldn't doubt that. So as far the wire paths go, see what is on your car and how it matches up.

Mine have those grommets going through the firewall.

 

[RustyRatRod]

No way the ammeter should have a single set of speed nuts holding the gauge and wires. The factory used regular (and in most cases copper) threaded double nuts. One set of nuts held the gauge to the housing(with a special insulator washer underneath) and second set of nuts to hold the wires. As long as everything is clean and tightened properly, the system works just fine in a stock car. Now, you start adding accessories and upping the draw on the system, you'll need to make some mods.....one of which might be to bypass the ammeter. That would depend on the added load.

I didn't say the wires, too. LOL

 

[Dartfreak75]

No way the ammeter should have a single set of speed nuts holding the gauge and wires. The factory used regular (and in most cases copper) threaded double nuts. One set of nuts held the gauge to the housing(with a special insulator washer underneath) and second set of nuts to hold the wires. As long as everything is clean and tightened properly, the system works just fine in a stock car. Now, you start adding accessories and upping the draw on the system, you'll need to make some mods.....one of which might be to bypass the ammeter. That would depend on the added load.

I think he is referring to the bezel itself

 

[RustyRatRod]

No way the ammeter should have a single set of speed nuts holding the gauge and wires. The factory used regular (and in most cases copper) threaded double nuts. One set of nuts held the gauge to the housing(with a special insulator washer underneath) and second set of nuts to hold the wires. As long as everything is clean and tightened properly, the system works just fine in a stock car. Now, you start adding accessories and upping the draw on the system, you'll need to make some mods.....one of which might be to bypass the ammeter. That would depend on the added load.

I admit.......when I typed that I was actually thinking about the temp gauge, but my point was that it all needs to be good and clean "back there".

 

[phaelax]

When I got my car mine was already bypassed, using a screw and some tape. Wanting to see all my gauges work, I hooked up the ammeter and it seemed fine for awhile. At this point I was running a 60amp alternator I think, (was 40a factory?) and one day I'm going down the highway and the dash starts smoking. Everything from the ammeter back to the bulkhead had melted! I've since rewired under the dash and put in new bulkhead connectors, but it's not fun. So is it necessary? I'd say in my case, definitely.

I like the sounds of that. I always hated how dim my headlights were

After a post from someone else on this forum, I replaced my lights with LEDs from a jeep wrangler. Minor shaving from the rear heatsink was required to fit, but after a few years they're still working 10x better than original. (though I rarely drive it at night)

 

[cudamark]

Actually in some cases it is BOTH the ammeter and bulkhead connector. The whole circuit is simply not heavy enough for heavy current applications. I melted the ammeter mounting bosses somewhat in my 70RR cluster way back in the mid 70's before Al Gore invented the internet. AND the same car suffered damage to the bulkhead connector terminals.

Even in 70?-72, some of the large sea barges used external shut ammeters which eliminated the problem. "Ma" knew the problem was there, as the cars with optional 65A alternators used modified harnesses to combat the problem. This is known loosely as "fleet police taxi" wiring. Look up in the 70--72-ish shop manuals, look up the optional 65A alternator wiring for the B bodies.

After I got out of the Navy (74) I saw a few Dodge ammeters melted from snow plow hoists, winches, or big driving lights. Looked EXACTLY like the photo in the MAD article, read it here:

Catalog

View attachment 1715603598

Yes, the '75-up pickups (and some other models) with the plastic housings were a real problem. Any current draw and the ammeter heats up. Add just a little more ( like a low/bad battery that is being charged for a long time) and the housings starts to melt. Once that happens, the connection between the ammeter stud and ammeter buss loosens causing a bad connection and some arcing which makes the housing (and eventually) the gauge to melt further. Whenever I have a truck dash apart, I solder the ammeter stud to the buss and not just rely on a crummy crimp fit.

 

[Mattax]

Mine have those grommets going through the firewall.

As you might infer from @zkx14 in that post, those type of wire grommet feed throughs were used for many purposes.
Those are one thing to look for and IF one of them has wires that are 12 gage or larger, that might be a grommed used for the battery feed.
If they look just like the ones on his car, (wire colors, size, and location) then its probably the same as his car.

So as far the wire paths go, see what is on your car and how it matches up.

Another thing you can do, and I think it would be good to do just to learn your car's wiring better, is follow the power feeds.

Below is a stripped down wiring diagram of a standard option power scheme (up to '75/76).
Use it while looking at your car.

Begin with the battery positive. At minimum there will be one very large wire to the starter, and 10 ga wire to the starter relay.
If you find other wires, note that down. For example some cars have power for hazzards wired in at the battery.
From the starter relay to the firewall the battery feed should connect into a fusible link. Then the link into either a wire or connection at the firewall.
The battery and alternator power connections at the bulkhead connector were usually sealed.

Now if the harness wrap is still on the wires its more difficult to follow the wire. Knowing where to look for it to show up helps.
You can see a nice example in this photo of the firewall of @zkx14 Duster.

The white arrow indicates the flag on the fusible link.

Something else you can do to follow a wire is to use an ohmeter or powered test light to see if the wire ends you are looking at are connected.
To do this:
Disconnect the battery. I generally remove the ground connection first, then the positive.
Then connect the meter to the disconneted battery positive clamp. Touch the other probe to whatever wire end or terminal you are looking at.
If there is no resistance or the light turns (or beeps) then you know the ends of the unknown wire are connected.

The alternator output is more difficult to follow because in a standard wiring it goes direct to the firewirewall connector, then to a welded splice where it conencts with the other feeds. That's all sealed except on the inside of the bulkhead connector.

 

[RedFish]

If a volt gauge is on a hot at all times circuit, it is a constant battery drain.

 

[RustyRatRod]

When I got my car mine was already bypassed, using a screw and some tape. Wanting to see all my gauges work, I hooked up the ammeter and it seemed fine for awhile. At this point I was running a 60amp alternator I think, (was 40a factory?) and one day I'm going down the highway and the dash starts smoking. Everything from the ammeter back to the bulkhead had melted! I've since rewired under the dash and put in new bulkhead connectors, but it's not fun. So is it necessary? I'd say in my case, definitely.


After a post from someone else on this forum, I replaced my lights with LEDs from a jeep wrangler. Minor shaving from the rear heatsink was required to fit, but after a few years they're still working 10x better than original. (though I rarely drive it at night)

Yeah, but "WHY" did you have that failure? I just bet it wasn't "just" because of the 60A alternator. Sounds like something found ground that shouldn't have. Did you ever find out what it was?

 

[phaelax]

I chocked it up to old bad wires. From what I could tell, and I'm no expert, but it looked like the source of the issue started with the wire overheating and melting the plastic around it in one spot then just spread into the cluster of wires it was tied up with.

 

[RustyRatRod]

I chocked it up to old bad wires. From what I could tell, and I'm no expert, but it looked like the source of the issue started with the wire overheating and melting the plastic around it in one spot then just spread into the cluster of wires it was tied up with.

Yeah, that "welded splice" deal behind the cluster wasn't the "best" idea in the world.......although honestly, I've seen very few failures of them. Mostly melted bulkhead connectors. Although mine has zero signs of even getting hot, that's one mod I might do. Separating those connectors and bringing them through in their own dedicated grommet through the firewall. Maybe. lol