Got a weird 1, been having lots of issues with oriellys alternators been through 4 because they are junk the last 1 jumped up to 18.2 volts at 1 point on my voltage gauge and maxed out the alternator gauge on the dash, switched over to autozone alternators no problem so far but now my dash lights will not turn off on my 72 dart after that alternator did that, it's intermittent but it's been draining the battery and not sure where to look, I tried the headlight switch because thats what caused them to turn off before playing with the dial but I reached in the dash and un plugged the switch and they stayed on, ive looked over the basics so far making sure i got no melted wires or pinched together wires and so far have not seen anything, have not pulled the instrument cluster it's self out yet, I have a car show tommorow so I just disconnected the battery cable for tonight, included a pic of the back of the instrument panel I can access without pulling it, since I haven't got to that yet and the voltage i saw on my voltage gauge, i also replaced the voltage regulator with the alternator and everything has been fine since then other then the dash lights problem
Dash lights will not turn off!! 72 dart
- Thread starter RobertC99
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Your high charging could be a dirty or bad buklhead connrctor and the dash lights could be a bad ground that's what i would check first .
Thanks for the reply, I've got the high charging fixed but I'll go through and check everything out too, it was something faulty on the alternator I took a multimeter and the stud on the alternator was 18.2 volts jumped over 19v at 1 point too, but I'll have to check the grounds for the dash for sure
Yes we can see the damage. Any time the 'alternator gage' is maxed damage will occur. The only unknown is how much damage and how soon. The gage is showing current. Current is electrons moving. The gage indicates how many electrons moving through it - litterally around the base of the needle causing a magnetic field that moves the needle. Needle fully at C = Battery charging 40 amps (way too much). Needle fully at D = battery discharging 40 amps, also way too much.
Please do not drive the car with the alternator uncontrolled. Alternator producing power around 18 Volt will burn things up, and cook the battery.
You've probably noticed that items provided electricity at higher voltage, will draw more power.
For example, turning on the headlights with the engine off, the lights are dim. This is because they are only getting battery power at 12.5 Volts. When the engine is running, they are getting power from the alternator - approximately 14.5 volts. The bulb draws more current when the voltage is higher.
When voltage is high enough, the bulb will draw so much current it burns out right away.
The battery is similar,except it will cook the acid.
More about battery charging here
Charging Battery with Alternator - Warning
We've discussed this here more than a few times. Usually about how easy it can be to cook the battery or overloading the charge wiring. Here's another reason. "Any attempt to charge a low battery by the alternator will result in stator windings burning out" ebay item # 222689173585 This is...
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This is a regulation problem. The alternators may be contributing to it, but the problem that needs to be fixed is the circuit.
If you have a hand held multimeter you can narrow down the issue.
With the engine running check the voltage at several locations. The question we want to answer is what voltage is the regulator sensing compared to the voltage the alternator is generating?
Measure: Voltage at alternator output compared with voltage at alternator feed (blue wire), and/or compared with votlage where the blue wires are joined at the ballast resistor.
Those are the two closest locations in the curcuit to the regulator's sense terminal.
If there is a voltage difference between the alternator output and the field terminal, then some or all of the problem is in the circuit.
If the output voltage varies with rpm (increasing together) then the regulator is damaged (full fielding).
Replacement alternators can contribute to the problem when they have been built with rotors that draw twice as much current as the factory intended. I suspect that many regulators can not handle the higher field current. Higher field current also magnifies any resistance in the circuit wiring.
67Dart273
Well-Known Member
Don't forget, Mattox the high charge problem could be right at the alternator---the infamous wrongly configured field connections
Anyhow the lights...........Only thing I can think of is that you overheated the harness with the charge problem, and it internally melted some wiring and crossed wiring
It is IMPORTANT that you understand how this works
Power for the instrument lamps in the headlight switch comes from the tail/ park part of the switch. First make certain those are coming on/ off properly with the switch.
That circuit feeds power TO the dash dimmer control
Does the instrument dimmer (twist the headlight switch knob) have any effect?
Now the dimmer control feeds it's output, on tan, down TO the instrument fuse in the fuse box. This is the ONLY fuse that works this way. From that fuse, ALL dash dimmer controlled lighting is fed out on ORANGE wiring
Next pull the INST fuse. This is normally located at one end of the fuse box.
If that kills the lights, then you either have a harness "cross," or some modification by you or others in the harness has caused a problem
Anyhow the lights...........Only thing I can think of is that you overheated the harness with the charge problem, and it internally melted some wiring and crossed wiring
It is IMPORTANT that you understand how this works
Power for the instrument lamps in the headlight switch comes from the tail/ park part of the switch. First make certain those are coming on/ off properly with the switch.
That circuit feeds power TO the dash dimmer control
Does the instrument dimmer (twist the headlight switch knob) have any effect?
Now the dimmer control feeds it's output, on tan, down TO the instrument fuse in the fuse box. This is the ONLY fuse that works this way. From that fuse, ALL dash dimmer controlled lighting is fed out on ORANGE wiring
Next pull the INST fuse. This is normally located at one end of the fuse box.
If that kills the lights, then you either have a harness "cross," or some modification by you or others in the harness has caused a problem
DASH LIGHTS
Now to your question about the dash lights.
The instrument lights, radio light, and similar options are a branch from the parking and tail light circuit.
That branch occurs inside the headlight switch.
-> Power goes in the B2 terminal and then can split off through the dimmer control.
- > Power then goes out the I terminal to the 3 amp fuse in the fuse box.
-> Power leaves the fusebox on an 18 or 20 gage orange wire(s) going to the instrument & radio lamps.
To figure out why its not turning off, one approach might be to check for power at the 3 amp fuse. If its has voltage, pop the fuse. If the side feeding the lamps still have power - then its a cross wire short. If only the input side has power, then its headliught switch or wire going out of it.
(edit; Treed! )
Now to your question about the dash lights.
The instrument lights, radio light, and similar options are a branch from the parking and tail light circuit.
That branch occurs inside the headlight switch.
-> Power goes in the B2 terminal and then can split off through the dimmer control.
- > Power then goes out the I terminal to the 3 amp fuse in the fuse box.
-> Power leaves the fusebox on an 18 or 20 gage orange wire(s) going to the instrument & radio lamps.
To figure out why its not turning off, one approach might be to check for power at the 3 amp fuse. If its has voltage, pop the fuse. If the side feeding the lamps still have power - then its a cross wire short. If only the input side has power, then its headliught switch or wire going out of it.
(edit; Treed! )
Thanks very much for the reply I believe that's what happened with the alternator because I took it out and got it tested and it failed every test, got a new 1 and the high charging is gone, before I got it tested I put a multi meter on the back of the alternator and it was reading 18 volts as well directly off the alternator, but the high current issue is fixed now I also put in a new regulator too after that happened
I will have to check all this I can pull the switch in and out and control the park ights and the headlights like normal
The dimmer has no effect, after the 1st time it happened I was able to turn the dial and everything went back to normal for a couple days but now they are back to being stuck on and it has no effect, I will have to go out and try pulling the fuse next thats the only thing I haven't done other then pulling the cluster and inspecting that
Thanks very much for the information I parked the car once this happened I have fixed the high charging already it was the alternator it's self something happened to it and my multimeter was reading 18 volts directly off the alternator it's self, I replaced it and the regulator and that has gone away
Sounds like it might be in the switch.
Dana has disassembled a switch for repair and posted photos. edit Found it 67 Dart Headlight Switch Demystified
Removing the switch is a bit of a pain.
Need to be able to hold the side button so the shaft with knob will pull out. Then unscrew the nut (there's a tool or you can make do with a snap ring or needle nose pliers. Then unlip the wiring connector.
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Thats what I was kinda afraid of, I have a similar issue with my wiper switch but it's the 3 speed with the washer and I have been having a hard time finding a switch for that 1, I turn the wiper switch and they just go full speed or nothing and they won't turn off till you turn the key off, or sometimes you can turn the key off and they just stop and won't go back to the down position, or when it rains they just randomly turn on by themselves
Bad thing I just put the battery cable back on and started the car and the dash lights are off, it's been intermittent so it will be kinda hard to find the source if it's not acting up, it's been doing it off and on the lights were off for a couple days then i got in the car 1 day and they were stuck on again
Thanks again for the information everything was normal till I was about to leave the car show and the dash lights were stuck on again, it's just odd that it's so randomly happening tried twisting the nob again no change so once I got home I pulled the fuses and no change, going to get the instrument cluster out again and pull the switch off and check it over along with the wiring next
67Dart273
Well-Known Member
The simple answer is that if you pull the INST fuse and the lamps stay on, there is a cross in the harness somewhere, OR someone has tried to add something to the ORANGE dash lighting and is backfeeding power into them. Look around your added gauges, tach, etc.
Yep just solved it, not sure what happened but found this in the harness behind the instrument panel, going to see how deep it gets and start repairing it
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67Dart273
Well-Known Member
Those can be a mess. I recommend you spend the time to pull that section out and inspect it. Work? You bet. Remember, these originally were installed or replaced with NO cutting. You may not need to pull it ALL out. Pull some out and if you see the "melt" becoming less, try to identify the affected harness colors and purpose by following them to the branch connector. AKA is it the radio, etc. You can tap/ tie/ zip tie unwrapped branches to keep them in proper location. Once you get back to "goo" wire and are convinced there "is no more" further along, then you can splice/ repair / replace wires, etc.
Try to note what you have done so you have some idea as to the cause. AKA let's say there was some sort of short internally in the headlight switch or some such. It would be a shame to repair all that and get a "repeat."
Try to note what you have done so you have some idea as to the cause. AKA let's say there was some sort of short internally in the headlight switch or some such. It would be a shame to repair all that and get a "repeat."
Thanks very much for the help!
I went ahead and I tracked the entire circuit end to end and narrowed down the damage it starts at the bulkhead connector and goes all the way just before the fuse box area, just ordered the bulkhead block and the connectors and I'm going to run a new brand new wire from the alternator back, so far i have only seen damage on the dash light circuit and the alternator output circuit, it's defently a mess, thankfully it's not the worst I have seen, im a mechanic but I just wasn't too familiar with how the wiring is done on my dart especially because diagrams are hard to come by, I just had to remake an entire section of harness on a lincoln that got chopped up,
Wiring diagrams are in the service manual(s). '72 may have a Body Manual with additional electrical diagrams. Earlier years everything is in the chassis diagram. www.mymopar.com --> service manuals
The diagrams will show which wires connect to which position in a connector. They are generally accurate although occassional mistakes will be found, and sometimes the exact routing was probably changed when the harness went into production. For example a junction will be mae at a terminal rather than welding a splice.
Alternator output wire.
Some of us have run a second parallel wire to the ammeter. This provides a shorter path for battery charging while keeping the original path to the main splice. A similar arrangement using a wires through a grommet was implemented on cars with rear defrost grids, and another variation on this idea was provided as a 'fleet' option with higher output alternators (and larger batteries too).
Search for those terms and you should turn up at least a few posts showing each of these wiring arrangements.
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diagram of what I changed on my '67
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and a photo Factory ammeter
The diagrams will show which wires connect to which position in a connector. They are generally accurate although occassional mistakes will be found, and sometimes the exact routing was probably changed when the harness went into production. For example a junction will be mae at a terminal rather than welding a splice.
Alternator output wire.
Some of us have run a second parallel wire to the ammeter. This provides a shorter path for battery charging while keeping the original path to the main splice. A similar arrangement using a wires through a grommet was implemented on cars with rear defrost grids, and another variation on this idea was provided as a 'fleet' option with higher output alternators (and larger batteries too).
Search for those terms and you should turn up at least a few posts showing each of these wiring arrangements.
---
diagram of what I changed on my '67
NJ and area Mopar carbecue - 5/22/21 for FABO and FBBO
It will be Saturday 5/22/21 at 1 PM. It’s BYOB and either a side dish or dessert. We will have burgers, dogs, water and soda. This is a no cost picnic, just a free hangout and eat get together. We love all Mopars no matter what shape they’re in. So bring whatcha got. Come even if you have to...
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I have not I didn't know there was online manuals, I had looked before just was never able to find much till now I have been using the Hanes book manuals but they are not complete ive tried following some of the wires on the page and it does not show the complete circuit for some of it or some things are missing conpletely, some of my friends were saying to go ahead and bypass the ammeter, and my dad said he did this on his jeep also to prevent something like what I had happen
Its an all too common belief. As you can see your ammeter did not cause the problem.
The ammeter only shows what flows in and out of the battery.
Jeeps with electric winches or plows can have issues with the battery circuit because of the heavy load directly on the battery - the alternator tries to help and then has to recharge the battery. The circuit sees high current for extended periods of time.
On your car, unless your running a big amplifier or electric pumps off the battery, the only current through the ammeter is during start, and when recharging. On standard '72 wiring the alternator supplies power to the welded main splice. From there is goes to the main feeds. Obviously if the battery needs recharging, it goes there too.
@RedFish has posted that in his experience as a tech (including dealership) some of the early 70s model have water leaks in that area. Oxidation and corrosion will effect all exposed connections and that will cause ammeter issues. Also some of the ammeters seem to be more prone to problems. The main problem reported has been the studs getting loose. They're pressed into the plate. So if they get loose, they will only get worse. Some people have soldered them.
In your specific situation we know the alternator was providing power at 18-19 Volts.
If the battery is offered power at 18 Volts, current will flow through it and it will overcharge and boil the acid.
If the battery is already low, then it will overcharge, get hot and draw lots of current.
The ammeter will be over 20 amps Charge and stay there, sometimes even at idle rpms.
20 - 40 amps is not enough to damage anything immediately, but is plenty to get connectors and wires hot if it continues.
Keep in mind the alternator output line is carrying the power to recharge the battery in addition to everything else that needs power: Ignition, alternator field, brake lights, etc.
The ammeter only shows what flows in and out of the battery.
Jeeps with electric winches or plows can have issues with the battery circuit because of the heavy load directly on the battery - the alternator tries to help and then has to recharge the battery. The circuit sees high current for extended periods of time.
On your car, unless your running a big amplifier or electric pumps off the battery, the only current through the ammeter is during start, and when recharging. On standard '72 wiring the alternator supplies power to the welded main splice. From there is goes to the main feeds. Obviously if the battery needs recharging, it goes there too.
@RedFish has posted that in his experience as a tech (including dealership) some of the early 70s model have water leaks in that area. Oxidation and corrosion will effect all exposed connections and that will cause ammeter issues. Also some of the ammeters seem to be more prone to problems. The main problem reported has been the studs getting loose. They're pressed into the plate. So if they get loose, they will only get worse. Some people have soldered them.
In your specific situation we know the alternator was providing power at 18-19 Volts.
If the battery is offered power at 18 Volts, current will flow through it and it will overcharge and boil the acid.
If the battery is already low, then it will overcharge, get hot and draw lots of current.
The ammeter will be over 20 amps Charge and stay there, sometimes even at idle rpms.
20 - 40 amps is not enough to damage anything immediately, but is plenty to get connectors and wires hot if it continues.
Keep in mind the alternator output line is carrying the power to recharge the battery in addition to everything else that needs power: Ignition, alternator field, brake lights, etc.
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Put a headlight relay harness on the car and that's 9 amps that will never have to be shared on the alternator output wires or go through the bulkhead connector. 
Bonus is you get brighter headlights.
Bonus is you get brighter headlights.
Anything I post is taken from the service manual but stripped down to the circuits of interest for that particular discussion.
The service manual has the complete diagram.
The Master Tech Conference has a couple sessions about how to work with the diagrams.
MyMopar ---> master technicians service conference
Wiring Diagram Codes
Each line in my '68 Service Manual wiring diagram is coded (e.g., J2-16BL). The one or two letters at the end designate color (e.g., BL for "black"). I presume that the two numbers prior to the color designate wire gage. What is the meaning of the rest of the code?
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ive been going through and opening everything up since i got home from work and i think i found all of the damage, i think the battery and everything else is good it would still start and run just fine and drive after i replaced the alternator after the 18volt incident it was just that i had the dash lights stuck on and then i found all this but i will monitor and test eveyrthing
i also went to the mymopar website and got the manuals and diagrams thanks very much for that suggestion! like i was saying with the book i have the diagrams are not complete so i went down a rabbit hole trying to find information before on other things, i dont have anything big on my car that would draw alot of power outside the factory stuff, i have added in 4 gauges and a voltage gauge separate with a couple usb ports and a cigarette lighter so nothing major and those are not tied into the harness except for ignition power only as a signal for the relays i added, i made a seperate harness for power and ground for those not connected to the harness just the battery
on the water leak i have had a problem with that before where if it rains extremely heavy there would be a puddle under the column area
Anything connected at the battery will draw power through the battery feed/charge wires.
When the alternator is working the ammeter will show current flowing to the battery plus current flowing to whatever has been tied in at the battery.
That additional current is going through all those connections that were only intended for battery charging. This is the same issue as an electric winch tied to the battery. Consider doing a heavy duty "Fleet" alternator set up. My version is linked early in this thread. Where I have the MSD power, you can connect your new harness. It can even have its own fuse box etc, and you can use that for the power connection for a headlight relay.
What this does.
The ammeter then only shows battery charging and discharging. So it reads true.
The 16 gage fusible link continues to protect the 12 gage wiring from a battery short.
Current to any of the items connected at the new post comes direct from the alternator (assuming its running). This current no longer has to go through the 1/4" push-on type terminals in the bulkhead multiconnector.
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