• When you click on links to various merchants on this site and make a purchase, this can result in this site earning a commission. Affiliate programs and affiliations include, but are not limited to, the eBay Partner Network.

Amp meter elimination

The ammeter tells you where the power is coming from; battery or alternator. A volt gauge just tells you the voltage in the system. It doesn't tell you where the power comes from.
Not entirely true. When my alternator failed, the volt meter was reading 12v (battery) vs the normal 14-15 (alternator).

I also found that it WAS discharging at idle. Headlights would dim at idle and even more so with my foot on the brake. After a new alternator was installed and the contacts where cleaned it idles at 14-15v and absolutly no dimming of the lights. I think the oxidized contacts where the biggest problem.
 
Not entirely true. When my alternator failed, the volt meter was reading 12v (battery) vs the normal 14-15 (alternator).

I also found that it WAS discharging at idle. Headlights would dim at idle and even more so with my foot on the brake. After a new alternator was installed and the contacts where cleaned it idles at 14-15v and absolutly no dimming of the lights. I think the oxidized contacts where the biggest problem.
Oxidation and/or corrosion are usually the first things to look for. That, and bad grounds. Lol
 
Ive gone over the Mad diagram a few times and it seems simple enough. BTW many thanks to KhryslerKid for his help. My car is a convertible and off the red terminal on the amp gauge is a circuit breaker with a connection for the power top motor. I cant see how the top is not operable all the time as that terminal is always hot. So now with the black and red wire soldered together i was thinking of running a line off of the hot starter terminal to a circuit breaker and then to the wire that went to the original circuit breaker that was on the back of dash connected to amp meter. My question is what size circuit breaker? I was thinking 5 amps. What do you think? Thanks-------Forgot to thank Nacho so thank you also and all others
 
Mine is bypassed to prevent fire. Don't need it. Bypassed for 15 years. If not charging, you will know it.
Unless your going to get your gauge converted to Volts.....Grab the right size bolt/lock nut, screw the +/- together and shrink wrap/electrical tape them together.....Exactly, if you ever question charging. Turn on your headlights and watch the idle to rev change....I can care less if the battery is discharging at idle.....and if if goes the opposite way, well you can smell that from the engine bay!
 
I put a smaller pulley on mine, charges great at idle. Also my car has all original wiring and amp guage and hasn't caught on fire yet

I had a melt down, no fire so I disconnected the AMP meter and rewired a few things like MADD advised. ya just never can be sure when and
IMG_5235.JPG
if bad things might happen.


IMG_5232.JPG IMG_5234.JPG
 
Once again, you don't need to modify the original setup but just fix/rebuilt ( like the rust eats the sheetmetal and we rebuild, then the wiring needs the same ), and making it better now, begining with a good alt which is what factory never did and is the first culprit of all these fails... then the rest.

But, whatever... I already told and explained
 
Ive gone over the Mad diagram a few times and it seems simple enough. BTW many thanks to KhryslerKid for his help. My car is a convertible and off the red terminal on the amp gauge is a circuit breaker with a connection for the power top motor. I cant see how the top is not operable all the time as that terminal is always hot. So now with the black and red wire soldered together i was thinking of running a line off of the hot starter terminal to a circuit breaker and then to the wire that went to the original circuit breaker that was on the back of dash connected to amp meter. My question is what size circuit breaker? I was thinking 5 amps. What do you think? Thanks-------Forgot to thank Nacho so thank you also and all others

Hey Steve, first the reason your top is not "hot" when the key is off is because mopar uses a lower amp circuit to actuate the motor, kind of like an ignition switch, that small switch could never handle full starting amps, so they use a solenoid or relay to handle the amperage.

Next, if you do not want to drill your bulkhead fitting you do not have to, I see that as a great option, I agree, it will work, BUT I also do not feel great about doing it.

Heres the other options, all of which I have done,
1-drill another hole in the firewall or share an existing one, to run a well insulated/grommet fed 8g wire right to the fuse box feed.

2-Keep the bulkhead how it is, bypass or convert your amp meter to a voltmeter, BUT wire the alt to the starter relay and keep an eye on your bulk head connections, contact cleaner, dielectric grease, clean, dry connections and they wont burn up.

Most of the issues were old corroded wires and bad connections, I had a copy of a service bulletin given to Mopar service centers 45 years ago telling them at every scheduled service the bulk head connections should be unplugged, inspected, cleaned, greased, and resinstalled. They new it was a problem.

The drilling the bulkhead fix is great for people with old burnt bulkheads, but for someone who just spent $500 on a harness it may not make sense. Consider yourself the original owner now, and you can keep that weak point strong by taking care of it and never having an issue.

Some other issues that plagued these cars, was aftermarket items, such as radios, cbs, lighting, fans, and anything the factory didn't install. DO yourself a favor and switch every light you can to led, if you are running an aftermarket radio, pull that power separately with its own circuit breaker or fuse.

I know there is a debate about grease, some people say yay some nay, I have had cars long enough in new England to say, YAY, use the stuff, I use it on most connections in and out of the car, also they all are not created equal, this is the one I like.
https://www.amazon.com/dp/B00AFG4TD8/ref=dp_cerb_1

a little expensive but good stuff, if you do not want it everywhere here are the must have spots in my opinion
High beam switch, cover that thing with it
bulkhead fittings
column plug
door switch plugs
I also coat my tube fuses with it on the contact sides, the distributor plug, and orange box plugs. I also dab some on my outside open connections, battery, starter, relay, alternator.

Also if you like the clear stuff, you can put some of that clear dielectric tune up grease on the outside of the connector, in the back where the wires go in, use aq tip and cover the back side of all the connections, this keeps moisture out.
That little bit of time and material, and a quick inspection of all of them connections when you do you oil changes, you will live worry free..
 
Last edited:
And with ammeters every electric device needs to be feeded from ALT side of the ammeter, including EVERY added accesory. Never from batt.

Fuse box is on ALT side
Ign switch is on ALT side
Headlights are on ALT side


EVERYTHING IS ON ALT SIDE

Only device on batt side is the starter motor. That's why the anmeter doesn't read the load this takes.

That's part of the added stress on our cars, adding acc on batt post allong the years... SIMPLY WRONG

You can use the alt stud, the ammeter stud ( black side ) or an added junction somewhere ( engine or cab side ) to feed whatever but ALT side. Get a parallel path to the bulkhead or replace the original path removing terminals and using a thicker wire, but ALT SIDE.

NO NEED to remove or bypass the ammeter, just upgrade the alt and get a better path and you are DONE.

My car is ( well is on a body job ) a driver and trust me with this my ammeter BARELLY reads anything. Even with AC and lights on.

No reading, no load
No load, no heat
No heat, everything safe!

Just clean and tight conectors, better quality paths and good powerfull alt and you are done for everything. And still on original working system.

AND IMPORTANT! NEED UNDERSTAND THE AMMETER READINGS!

Once you understand how the charging system works, will understand why is not needed any mod but just upgrade.

Like when you upgrade your engine with more CR, camshafts and carbs? You study what do you want and what do you need to get more HP.. right? Well... take care of the same with electricity.
 
Last edited:
NO NEED to remove or bypass the ammeter, just upgrade the alt and get a better path and you are DONE.
Please define "upgrade the alt". Does that mean go to a higher output? I believe the factory was 30 amps. My replacement is 70. It would be nice to have the ammeter operating as it was intended, but not at the risk of a fire. I've heard so much pros & cons that I just don't know what to believe anymore and have mine bypassed just to error on the side of safety.
 
Yes. An alt able to give 45-50 amps iddling, what doesn't mean will source that all the time, just that is ABLE to give it.

An alt just gives what the car demands. You can get a thousand amps alt but if the car just demands 30 amps, the alt will provide just that.

I have talked about on earlier replies and also a link I posted where I explain how the system works

The bigger mistake factory did is the low capacity alts. Then the weak paths after that ( not really the wires like more the terminals ).

Read the link I posted
 
a car demanding 40 amps to work will suck that no matter if given by the alt or by the batt ( or both together ), so if you can keep the source just coming from the alt side of the ammeter, the load will be just on that side and will never ( or barelly ) go through the ammeter reading discharge.

If you never ( or barelly ) get a discharge, will never get a charge reading either. Reducing the readings on ammeter it means reduce the loads. No load---- no heat.

The ammeter is actually a BATT GAUGE not really an alt gauge. The alternator can't get a charge or discharge because is not an acumulator, is a producer. Just an acumulator can get a discharge!
 
This is what I did. Bybassed the ammeter, replaced it with a volt (red circle). Took red/black cut, spliced and soldiered together then heat shrink covering it (arrow)

Inkedthumbnail_20170225_192243_resized_LI.jpg
 
And with ammeters every electric device needs to be feeded from ALT side of the ammeter, including EVERY added accesory. Never from batt.

Fuse box is on ALT side
Ign switch is on ALT side
Headlights are on ALT side


EVERYTHING IS ON ALT SIDE

I just added 2 stereo amplifiers and fed the power to them directly from the battery. Where exactly should I be powering it from? I used a 4 gauge wire with a fuse and ran it straight off the battery. I haven't bypassed my ammeter, but I have run a wire with a fusible link between the alternator and the starter relay. I'm also installing a switch using the accessory power so I can power on/off the amps and eliminate the initial power draw when the car starts and the amps would power on at the same time. (not sure of that will even matter though)
 
Already told

EDITING.

Running the wire between starter relay and alt post is the same effect than bypass the ammeter, so won't care anymore where you feeds anything.
 
Last edited:
OK, read it. I have to tell you that electronics is not my strong point, but thanks to your thread, I understand this ammeter "problem" a little better than I ever have. I DID have the "normal" discharge, dimming lights etc. at idle. Always thought it was just the nature of the beast. After I had a stall and starting problem I found a badly oxidized battery wire at the starter relay. Cleaned it and every other wire I could get to. Bulkhead connections (believe it or not) where perfectly clean, but I cleaned more and put some dielectric grease on all the contacts anyway. When I attempted to pull the alternator wire (from what I believe was still the factory 30 amp alternator), it broke causing me to replace the alternator. I went with a 70 amp alternator (as I recall, but could have been 50 or 60) from Advance Auto Parts, and immediately noticed that at idle, my volts no longer dropped. They stayed at 14-15v and the headlights no longer dimmed (even with my foot on the brake). Based on your well written thread, I am much more comfortable reconnecting my ammeter and putting it back to it's original factory configuration. Having an inoperable gauge always bothered me. I'm a bit of a perfectionist.

P.S.
What caused me to finally bypass the ammeter was in trouble shooting an electrical gremlin, I found the ammeter studs loose. I figured as long as I had to remove them, I might just as well bypass the potential "problem". Looking forward to an operable, but relatively inactive ammeter. Thank you!

P.P.S.
The car is factory with no A/C. The only add on electrical accessory is a Tach.
 
Auto Transport Service
Back
Top