Confused

[Omni]

Good Day All
Not wanting to hijack other threads on this, so here is one more on the ammeter bypass.
What is the difference between the method that cbarge outlined (adding an additional wire from the alt stud to the starter relay), and the procedure where you run two wires directly to the ammeter bypassing the bulkhead connector?
As an aside the article that Big John linked: ( Some considerations about the charging and wiring upgrade and your worries about) was most informative especially if you add relays. Until I read that I never gave much thought to where the power comes from. Now, for any future upgrades, I will draw power from the the Alt side of the circuit. If I understand the article correctly, doing that will eliminate the load on the stock wiring (re:amp gauge).
Thanks to All who respond.
Omni

 

[carfreak6970]

I believe the difference would be that running a wire from the alt stud to the starter relay would not really "bypass" the ammeter. The ammeter would still be in the circuit but if it fails it wouldnt leave you stranded. However, in doing so not all the power is running through the ammeter rendering that gauge useless in accurately monitoring the charging/discharging of the system.

Running two wires directly to and from the ammeter would take the charging load off of the bulkhead connector, which in itself is a trouble prone area. But should the ammeter fail, you would be stranded.

It really all depends on the electrical load your car typically experiences (standard options it came with/running electronic fuel pumps, fans, powerful audio equipment, larger than stock alternators, etc.) and the condition of your connections, wiring and gauge.

 

[bronze turbine]

I think bypassing the ammeter under the hood but leaving it still hooked up would be a decent option. The ammeter would still function somewhat, but it would not be carrying a huge amount of current. And as stated, if it failed, the circuit would still be complete and you would not be stranded. If I understand correctly the main risk of not doing the ammeter bypass is the risk of fire under the dash. With only 1/2 or less of the current going through the ammeter I would think this risk would be correspondingly reduced. Also, if resistance got really high in the bulkhead connector or under the dash, rather than getting hot and burning up, more of the current would flow through the bypass. Still, it's probably best to bypass the bulkhead connector (and ammeter) completely, but you really won't have any indication of the state of your charging system, which is what the ammeter is there for in the first place.

 

[Big_John]

Good Day All
Not wanting to hijack other threads on this, so here is one more on the ammeter bypass.
What is the difference between the method that cbarge outlined (adding an additional wire from the alt stud to the starter relay), and the procedure where you run two wires directly to the ammeter bypassing the bulkhead connector?
As an aside the article that Big John linked: ( Some considerations about the charging and wiring upgrade and your worries about) was most informative especially if you add relays. Until I read that I never gave much thought to where the power comes from. Now, for any future upgrades, I will draw power from the the Alt side of the circuit. If I understand the article correctly, doing that will eliminate the load on the stock wiring (re:amp gauge).
Thanks to All who respond.
Omni

A couple things...

First, I'm not a believer in the ammeter being the devil that some think. Having loose connections, bad wires or having some really high draws through the system causes most of the problems that some claim. Second, there is so much misinformation thrown out by people that don't understand how the charging and electrical system works.

So... With that disclaimer (LOL)... One thing with the '65 (I'm assuming you are referencing your '65), it has a lot better connection at the bulkhead than the later cars. Keep that in mind when reading, as most everything written is aimed at late 60's/early 70's cars.

I haven't read the Nacho bypass thread in a while. I don't know why they would want 2 wires though. Was it to avoid one larger wire?

Here's what I think. If you want to add something like a headlight relay, that will actually take some of the draw across the ammeter/bulkhead connector. That's just more for you to think about. If you aren't adding anything that draws a lot, like a stereo amplifier, you may not really need to do the bypass at all... Or do the bypass like Cbarge has outlined.

I guess the question is "why do you want to do the bypass?" and then figure it out from there.

 

[PurpleBeeper]

I went the bypass the ammeter, but leave it hooked up route as bronze turbine mentions. It was easy and I've had no issue. My ammeter "kinda" works. It's not accurate at all, but I can see a big charge or big drain somewhat. It would tell me if my alternator went out for sure

 

[Ross Wooldridge]

A couple things...

First, I'm not a believer in the ammeter being the devil that some think. Having loose connections, bad wires or having some really high draws through the system causes most of the problems that some claim. Second, there is so much misinformation thrown out by people that don't understand how the charging and electrical system works.

So... With that disclaimer (LOL)... One thing with the '65 (I'm assuming you are referencing your '65), it has a lot better connection at the bulkhead than the later cars. Keep that in mind when reading, as most everything written is aimed at late 60's/early 70's cars.

I haven't read the Nacho bypass thread in a while. I don't know why they would want 2 wires though. Was it to avoid one larger wire?

Here's what I think. If you want to add something like a headlight relay, that will actually take some of the draw across the ammeter/bulkhead connector. That's just more for you to think about. If you aren't adding anything that draws a lot, like a stereo amplifier, you may not really need to do the bypass at all... Or do the bypass like Cbarge has outlined.

I guess the question is "why do you want to do the bypass?" and then figure it out from there.

I agree with this - the ammeter is generally NOT the issue, biggest issue is loose and corroded connections, bad repairs and the like. I've never had an ammeter fail, but I would expect it to fail if its connections were loose. If one has ever removed the gauge cluster, you've had to remove the connections to the ammeter (one says RED the other says BLACK), and typically, they're on there very tight with nuts and lock washers, and need to be returned to the same state when reinstalled. BE THAT AS IT MAY - IT'S ON THE PERSON RE & REING THE GAUGES.

Never seen an issue there, but I've seen lots at other places where problems crop up: the bulkhead being the main culprit, where those silly spade connectors are totally prone to corrosion, dirt, getting loose and being barely able to handle the load in the first place when they were new. John's statement that the 65s seem to have a better bulkhead connection for the black and red main wires going to the ammeter is something I'll leave on the table for 65 owners, but for everyone else with cars newer than 65, the bulkhead is in my opinion the weakest area in the whole charging circuit.

So, run unbroken wires in and out THROUGH the firewall - no spade connectors. To do this, you BYPASS the BULKHEAD, either by drilling new holes and using proper grommets, or what many do is run the new wires through the speedo cable grommet. That's what I did. You can choose to eliminate the ammeter altogether and just join the wires together with a proper union and the appropriate insulation (OR just connect them both to the same stud on the ammeter - which disables the gauge but keeps the connection protected like the factory designed), but then you can't monitor the charging system. Yes, if the gauge fails, you're stranded, but again, having owned these cars for the better part of 40 years, I've never had an ammeter fail. It's not the issue, unless someone's messed with it and left the connections loose.

Here's what I did, and I also doubly protected the whole circuit:

What protects that circuit? Well, the FUSIBLE LINK protects the entire car's electrical system by fusing the main power wire. It precedes the big red wire going into the ammeter from the power stud on the starter relay (typically found on the firewall or inner fender close to the battery). It's of course, often connected at the bulkhead with spade connectors. Silly.

What I did was get a decent little 8 spot terminal block (DO NOT USE ONE WITH A COMMON BUS BAR - each terminal has to be PAIRED WITH ONLY ONE OTHER TERMINAL, to facilitate a secure connection between two wires), and I ran the battery power from the relay on the firewall to it, then connect it to another terminal with a fusible link, THEN run it through the speedo cable to the ammeter. I then ran the black wire OUT to the terminal block and put a new fusible link on the new big black wire (keep in mind that the new black wire needs to be spliced in AFTER the big welded distribution splice under the dash that feeds all the rest of the car from the post ammeter black wire), running iy out through the speedo grommet, to a terminal on my new terminal block, connected to another terminal with a fusible link, and off to the alternator. Doubly protected, and all with nice terminals that are FAR better than spade connectors.


Here you can see the red wire coming from the battery to the terminal on the starter relay, and the fusible link goes to the terminal block rather than into the bulkhead. On the other side of that the new red wire goes off the terminal block and in through the speedo cable grommet to the ammeter.

Here you can see the black wire comes out from the dash through the speedo grommet to a terminal on the terminal block, and a new fusible link is installed to another terminal, and the new big black wire runs to the alternator.

 

[Just Carbs]

In 1975 the amp gauge failed on my 1968 Newport with 42k on the clock. AC car, no electric power options.

 

[mrfury68]

I ran a wire from the alternator stud to the starter relay to reduce the current going through the bulkhead to the ammeter. Ammeter still works, it just doesn't swing as wide either way. I also cleaned the bulkhead terminal and made sure the nuts attaching the wires to the ammeter are tight and clean. I'm also lucky, having owned my Fury since it was only 14 years old, no wiring was ever butchered or "modified" in any way. I'm confident my electrical system is solid and safe.

 

[Big_John]

I agree with this - the ammeter is generally NOT the issue, biggest issue is loose and corroded connections, bad repairs and the like. I've never had an ammeter fail, but I would expect it to fail if its connections were loose. If one has ever removed the gauge cluster, you've had to remove the connections to the ammeter (one says RED the other says BLACK), and typically, they're on there very tight with nuts and lock washers, and need to be returned to the same state when reinstalled. BE THAT AS IT MAY - IT'S ON THE PERSON RE & REING THE GAUGES.

Never seen an issue there, but I've seen lots at other places where problems crop up: the bulkhead being the main culprit, where those silly spade connectors are totally prone to corrosion, dirt, getting loose and being barely able to handle the load in the first place when they were new. John's statement that the 65s seem to have a better bulkhead connection for the black and red main wires going to the ammeter is something I'll leave on the table for 65 owners, but for everyone else with cars newer than 65, the bulkhead is in my opinion the weakest area in the whole charging circuit.

So, run unbroken wires in and out THROUGH the firewall - no spade connectors. To do this, you BYPASS the BULKHEAD, either by drilling new holes and using proper grommets, or what many do is run the new wires through the speedo cable grommet. That's what I did. You can choose to eliminate the ammeter altogether and just join the wires together with a proper union and the appropriate insulation (OR just connect them both to the same stud on the ammeter - which disables the gauge but keeps the connection protected like the factory designed), but then you can't monitor the charging system. Yes, if the gauge fails, you're stranded, but again, having owned these cars for the better part of 40 years, I've never had an ammeter fail. It's not the issue, unless someone's messed with it and left the connections loose.

Here's what I did, and I also doubly protected the whole circuit:

What protects that circuit? Well, the FUSIBLE LINK protects the entire car's electrical system by fusing the main power wire. It precedes the big red wire going into the ammeter from the power stud on the starter relay (typically found on the firewall or inner fender close to the battery). It's of course, often connected at the bulkhead with spade connectors. Silly.

What I did was get a decent little 8 spot terminal block (DO NOT USE ONE WITH A COMMON BUS BAR - each terminal has to be INDIVIDUAL), and I ran the battery power from the relay on the firewall to it, then connect it to another terminal with a fusible link, THEN run it through the speedo cable to the ammeter. I then ran the black wire OUT to the terminal block and put a new fusible link on the new big black wire (keep in mind that the new black wire needs to be spliced in AFTER the big welded distribution splice under the dash that feeds all the rest of the car from the post ammeter black wire), running iy out through the speedo grommet, to a terminal on my new terminal block, connected to another terminal with a fusible link, and off to the alternator. Doubly protected, and all with nice terminals that are FAR better than spade connectors.


Here you can see the red wire coming from the battery to the terminal on the starter relay, and the fusible link goes to the terminal block rather than into the bulkhead. On the other side of that the new red wire goes off the terminal block and in through the speedo cable grommet to the ammeter.
View attachment 641416



Here you can see the black wire comes out from the dash through the speedo grommet to a terminal on the terminal block, and a new fusible link is installed to another terminal, and the new big black wire runs to the alternator.

View attachment 641415

It's kind of refreshing to hear from someone else that doesn't think the ammeter was responsible for Jimmy Hoffa's disappearance.

For those that aren't familiar with the '65 bulkhead connector, the power wires connect to larger Packard 59 connectors that are 5/16" wide, the same as headlight connectors. Much more robust and isolated from the other wiring. After 1965, they went to the smaller Packard 56 connector that's 1/4" wide.

The connector cavities are in the center.

Concerning the newer cars, getting away from the bulkhead connector for the main power feed and running a wire through the firewall or even through a drilled hole in the bulkhead connector makes a lot of sense.

I do think that if you've done the "bypass" that adds a wire from the alternator to the battery (usually connecting to the starter relay) AND you've added a headlight relay, you don't need to do this. The amount of current flowing through the bulkhead connector is reduced quite a bit with those additions. I'd even say that doing the "bypass" reduces it enough. My '70 is wired like that with headlight relays and the "bypass".

Now once you add something with a lot of draw, like a stereo amp or similar, you really need to do these mods. If you have minimal draws, stock alternators etc. like my 65's with no A/C for example, the need to do the mods drops down quite a bit.

While this doesn't mean anything in this thread, one other thing to note is with a '70 and up, you'll often have a fault at the connector under the steering column that will almost always destroy the connector. Get up to about 1973 and many cars also have a shunt type ammeter that doesn't carry all the current through it and even some have the "bypass" already in the wiring harness. But that's another subject for another day.

Now... I'm not saying that these mods shouldn't be done.... Never a bad idea at all. I just want guys to understand why or when you need to do it. It's really some basic high school physics class stuff that makes some eyes glaze over. LOL

To me, having good connections with good wire is much more important and often overlooked. I've joked about how guys are having electrical problems and come to find out that their car has had its harness hacked up and someone has used lamp cord and Romex to repair it or add on some accessories. While that is an exaggeration, it's not unusual to see things like Scotchlocs and twisted wire connections.... and they wonder why there's electrical problems.

 

[cudamark]

I too have only seen ammeter failures due to human error (not counting overload/overcharge mods which can do it too), where the terminal posts were twisted, nuts cross-threaded, or other such butchery, EXCEPT for '75-80 D-series pickups with the plastic instrument cluster housings. Those ammeters have a design flaw in that the terminal posts are just pressed through the main buss bar of the gauge. Over years (and/or loads) of use, the housing warps a bit causing the post to loosen at the buss. This caused arcing, heat, and more warping/melting of the housing which eventually causes a failure......and sometimes a fire. I have converted my trucks to the '72-4 metal housing, and have soldered the posts to the buss to eliminate that potential problem. There may be other models with that design that I'm not aware of, and a similar soldering job along with proper insulating washers might help those models too.

 

[live4theking]

2017 my older two kids and I took our 68 NYer to Carlisle. That spring I'd been having an issue with intermittent power loss, all power. While at Carlisle it died. I had trying to locate the issue, but intermittent electrical issues can be the worst.

Sunday morning while waiting for the tilted to come for the ride home I was taking to a guy that said he's seen the same problem in numerous old molars and suggested I pull the dash a tighten the nuts on the back on the ammeter because the fiber insulating washers dry out and shrink. I was going to check the ammeter because I thought it failed open. Turns out the nuts were just loose.

After running it long enough to ensure the problem was fixed I did the simple bypass with a fusible link.