74 duster elelctrial help

[townsend]

The grommet on the firewall is most likely for factory AC.
nick0705 can confirm if it originally came with air conditioning.
Three places need close examination for any signs of damage, like burning or melting.
Fuse box, ignition switch connector to dash connector and inside firewall bulkhead connectors.

 

[Mattax]

Okay so I traced these 2 wires going into the firewall. This is what I found. The red wire from starter relay through that 30amp inline fuse goes through the harness in the dash to the ammeter plus side on the gauge. The other wire is the alt feed wire it’s green going though the wall and as you can see in the second picture with the butt connector the wire came out when I pulled the electrical tape off.

Rereading this, I think what you are saying is the two wires above the bulkhead connector are the two power feeds. They really really need to have an insulating bushing where the wires go through the sheet metal. Maybe they have a small one and its just not visible, but its really important.

Also now I think what you are saying is the feed wires, at least some of it, is smaller than 12 gage. Yes you can make those 10 gage, although 12 gage will do. If you can buy marine grade wire, its tinned and a little denser than automotive wire of the same gage.

So now I'm guessing there was a problem with the original feeds through the bulkhead connector. One option to consider is copying one of the heavy duty or fleet wiring schemes. Basically what that means is running those two feeds through a heavy grommet.

or

There are dimples in the firewall to locate where grommets would be placed.
Then to connect the power to the main splice, use the original standard connection, and if its serviceable, the original alternator feed through the bulkhead. That provides parallel feeds, and both are still protected by the fusible link or a maxi-fuse.


Here's a factory HD wiring version on '74 .

 

[Mattax]

The heavy wires are more difficult to crimp.
I don't know of a way to replicate the sealed ring terminal crimps like these.
Best can do is heat shrink to seal the moisture out as well as covering the hot conductors..

 

[Mattax]

Here's the attempt to compare maxi-fuse to fusible link.
If the maxi-fuse is slow blowing, I would think 40 or 50 amp probably is a reasonable balance between protecting the 12 gage wires while not so sensitve as to melt when there is a brief spike in current.

Electrical Issues - MiniMopar Resources

 

[nick0705]

The grommet on the firewall is most likely for factory AC.
nick0705 can confirm if it originally came with air conditioning.
Three places need close examination for any signs of damage, like burning or melting.
Fuse box, ignition switch connector to dash connector and inside firewall bulkhead connectors.

Yes it does have AC doesn’t work but it is still on the engine. I did inspect all those areas there are no signs of damage or burning.

 

[nick0705]

Rereading this, I think what you are saying is the two wires above the bulkhead connector are the two power feeds. They really really need to have an insulating bushing where the wires go through the sheet metal. Maybe they have a small one and its just not visible, but its really important.

Also now I think what you are saying is the feed wires, at least some of it, is smaller than 12 gage. Yes you can make those 10 gage, although 12 gage will do. If you can buy marine grade wire, its tinned and a little denser than automotive wire of the same gage.

So now I'm guessing there was a problem with the original feeds through the bulkhead connector. One option to consider is copying one of the heavy duty or fleet wiring schemes. Basically what that means is running those two feeds through a heavy grommet.
View attachment 1716430934
or
View attachment 1716430931
There are dimples in the firewall to locate where grommets would be placed.
Then to connect the power to the main splice, use the original standard connection, and if its serviceable, the original alternator feed through the bulkhead. That provides parallel feeds, and both are still protected by the fusible link or a maxi-fuse.


Here's a factory HD wiring version on '74 .
View attachment 1716430930

Mattax, yes you are correct those two wires they ran through the firewall are power feeds. You are also correct there isn’t any kind of insulating bushing where they go through which I will have to fix that. So if I’m reading that second diagram correctly I would run a new 12ga wire from alternator directly to the ammeter while keeping the other one hooked up the way they have it ? I also think I’m going to run a new red wire from stater relay with a fuseable link closer to the relay then through a insulating bushing directly to the other side of the ammeter. Do you think that’s the best way to do it do both wires in 12 guage with a 16 guage fuseable link on the red wire closer to the stater relay. This would delete that 30amp mini fuse that is inline or leave the red wire the way it is ?

 

[Mattax]

Lets sart by illustrating what you have found.
Here's what seems to have been done. Correct me as needed.
The previous owner spliced into the A1 (battery) and the R6 (alternator) and routed each through a hole above the bulkhead multi-connector. The fusible link was replaced with a 30 amp fuse. Yellow insulated butt connectors were used for the splices.

or maybe the green wire goes all the way to the alternator? and the fuse is a new wire all the way to the starter relay?

You are also correct there isn’t any kind of insulating bushing where they go through which I will have to fix that.

That sounds good. Whetehr you can find a grommet as heavy as the factory may not be practical, but some sort of grommet for the wires whether seperate or together is definately needed.

So if I’m reading that second diagram correctly I would run a new 12ga wire from alternator directly to the ammeter while keeping the other one hooked up the way they have it ?

Yes that's what I drew but now knowing what you found, I think we can be pretty sure the original line is gone or damaged. Look at the bulkhead positions J and P.

One or both are probably empty and or damaged. If so there is no point in reusing them unless you were restoring the car to be 100% original. IF they are are in good shape, then maybe its worth restoring the original alternator circuit as a parallel feed. Splitting the alternator output is fine. But there are other ways to do this that could be easier. On the engine side you can look for the bump outs on the connector to get the orientation. On the inside of the car, with a flashlight you'll see the letters are molded in the plastic.

I also think I’m going to run a new red wire from stater relay with a fuseable link closer to the relay then through a insulating bushing directly to the other side of the ammeter.

That would be fine.

Do you think that’s the best way to do it do both wires in 12 guage with a 16 guage fuseable link on the red wire closer to the stater relay. This would delete that 30amp mini fuse that is inline or leave the red wire the way it is ?

There should be just one red wire to the ammeter. Having two paths will reduce the effectiveness of the fuses or fusible links. One fuse or fusible and one line.

How to do it: The challenge is the joining different wire sizes together. That would be the advantage of using 12 gage wire. You can splice connect 12 gage to 12 gage with a good splice. For the 16 ga fusible link the factory way was crimp each end to a terminal.
By 1974 they were using a bullet connector with white plastic housing that locked together. I don't recall anyone finding a source for those connectors. Might be a Molex product.
Here's a NOS Chrysler link with ring terminal to go on the starter relay (not mine)

Below is a repop I bought that also connects at the starter relay but then plugs into the bulkhead connector. That's for a model with the starter relay on the firewall.

I've seen links that come with a ring terminal on one end and the other stripped for whatever terminal you want to install. They're not blue because the color codes were not standardized, but that's an option you may find in the parts store.
I can't find the photo right now.

Alternator output.
As far as running a new alternator output wire, lets see what you find at the alternator itself. Chrysler used a couple different ways to insulate around that stud. See what s there and what condition its in and then decide whether to run two wires in parallel or one.

The engine connectors are a common problem area, sometimes even the seperate dedicated R6 wire bullet connector.

There's a '74 service bulletin for C-bodies to replace that connector with a splice if its showing signs of damage. TSB 8-6-74

The 1970 Hamtramck Registry "1974 DODGE MODEL TSBs Index" Page

page 4 shows the damage

https://www.hamtramck-historical.com/images/TSBs/1974/08-06-74D%20page4.jpg

 

[townsend]

In post 32 Mattax shows bullet connector R6
The connector looks to be covered in black electrical tape.
The factory never taped that white bullet connector.
How about a picture or description of that connector with the tape removed from R6.

 

[67Dart273]

Those ammeter connections look like...............................

 

[Mattax]

Gotta wonder if that car was in a real humid location or had a windsheild or cowl leak. Its prob would be worth cleaning every connection.

 

[67Dart273]

Lets sart by illustrating what you have found.
Here's what seems to have been done. Correct me as needed.
The previous owner spliced into the A1 (battery) and the R6 (alternator) and routed each through a hole above the bulkhead multi-connector. The fusible link was replaced with a 30 amp fuse. Yellow insulated butt connectors were used for the splices.

View attachment 1716431007
or maybe the green wire goes all the way to the alternator? and the fuse is a new wire all the way to the starter relay?


That sounds good. Whetehr you can find a grommet as heavy as the factory may not be practical, but some sort of grommet for the wires whether seperate or together is definately needed.

Yes that's what I drew but now knowing what you found, I think we can be pretty sure the original line is gone or damaged. Look at the bulkhead positions J and P.
View attachment 1716431008
One or both are probably empty and or damaged. If so there is no point in reusing them unless you were restoring the car to be 100% original. IF they are are in good shape, then maybe its worth restoring the original alternator circuit as a parallel feed. Splitting the alternator output is fine. But there are other ways to do this that could be easier. On the engine side you can look for the bump outs on the connector to get the orientation. On the inside of the car, with a flashlight you'll see the letters are molded in the plastic.



That would be fine.

There should be just one red wire to the ammeter. Having two paths will reduce the effectiveness of the fuses or fusible links. One fuse or fusible and one line.

How to do it: The challenge is the joining different wire sizes together. That would be the advantage of using 12 gage wire. You can splice connect 12 gage to 12 gage with a good splice. For the 16 ga fusible link the factory way was crimp each end to a terminal.
By 1974 they were using a bullet connector with white plastic housing that locked together. I don't recall anyone finding a source for those connectors. Might be a Molex product.
Here's a NOS Chrysler link with ring terminal to go on the starter relay (not mine)
View attachment 1716431018

Below is a repop I bought that also connects at the starter relay but then plugs into the bulkhead connector. That's for a model with the starter relay on the firewall.

View attachment 1716431014

I've seen links that come with a ring terminal on one end and the other stripped for whatever terminal you want to install. They're not blue because the color codes were not standardized, but that's an option you may find in the parts store.
I can't find the photo right now.

Alternator output.
As far as running a new alternator output wire, lets see what you find at the alternator itself. Chrysler used a couple different ways to insulate around that stud. See what s there and what condition its in and then decide whether to run two wires in parallel or one.

The engine connectors are a common problem area, sometimes even the seperate dedicated R6 wire bullet connector.
View attachment 1716431020

There's a '74 service bulletin for C-bodies to replace that connector with a splice if its showing signs of damage. TSB 8-6-74

The 1970 Hamtramck Registry "1974 DODGE MODEL TSBs Index" Page

page 4 shows the damage

https://www.hamtramck-historical.com/images/TSBs/1974/08-06-74D%20page4.jpg

That reminds me. A 74 should have that WHITE underhood engine harness connector. That was included to easily allow the engine, with part of the harness installed, to be plugged right into the engine bay harness. Redfish has LONG recommended cutting it out and replacing it. It ALSO has the main alternator output wire incorporated in that connector. It is one of or the ONLY white connector in the engine bay

 

[Mattax]

There's a '74 Service Manual for sale in the 'Other items' forum.

 

[67Dart273]

I've told many of these guys.........I have a copy of the digital manual. All you have to do is contact me, get my address, and MAIL me a thumb drive with a prepaid return mailer. You get the body and chassis manual free. They are too big to upload, at least for me.

Body manual is just under 110MB, Chassis manual is 416MB, so you are looking at half a gig

 

[nick0705]

Thanks everyone for your inputs. Yeah idk what they had going on but here’s a update where I’m am. New ammeter wires are ran and protected along the way I found a few wires broken and some exposed wire. These have been repaired. I’m going to assume between the wire connector that I sent a pic of that came disconnected was def a problem and there was a wire off the alt blue I believe touching metal. All the wiring has been repaired and rerouted. I’m waiting on a new headlight switch since I’m already right there and the connections on it look rough. It should be here tomorrow along with some loom to secure the harnesses behind the dash once all that is done I’ll hook up power and see what happens. I did the 12guage wire and a 16guage fuseable link from the stater relay to the ammeter. So we shall see how this turns out tomorrow.

 

[Mattax]

I still think that before you hook up the battey cable it would be worth
1. checking for shorts to ground. Clip the meter onto the disconnected positive cable or at the starter relay. If it open circuit, then disconnect the voltage regulator and the ingition box. Turn the key to run. Should remain open or show the resistance of the choke assist and/or any idle solenoid.
2. Slow charging the battery on a charger.

When you hou hook up the battery cable, check the ammeter immediately for any discharging. Open the door to turn on the dome light and it should move just a little.

When starting, watch the ammeter and shut down if the needle goes to extreme in either direction. 20 or 25 amps charge briefly is OK. It should drop to 5-10 charging quickly.


Headlight switch. Just know that new switches almost always come with a 20 amp breaker instead of a 15 amp breaker. By 1974 A-bodies were being sold with the newer 6014 seal beams, but the wire sizes remained the same 16 gage to the dipswitch and 18 gage to teh lamps. If you will be driving at night with sealed beams or H4 typ lamps it is worthwhile to install a relay for the headlights. It sends the current to the headlights directly. This reduces the maximum current the alternator output wire will have to carry. Less current through any wire or connection means less resistance and less chance of heating and damage.

It also shortens the path and reduces the connections to the headlights. The result is less resistance, less voltage loss, and brighter headlights.
For example here Stern has a table showing that just .3 V loss can drop the light output by a couple hundred lumens. Daniel Stern Lighting Consultancy and Supply

Headlight Relay harness can be bought ready to install.

[FOR SALE] - Plug and play - Headlight Relay Kits

Headlight relay kits that are essentially plug and play. There is a substantial increase in voltage at the headlight, increasing light output performance. Light output degrades exponentially with voltage input reductions. These kits also take headlight amp loads off the fragile bulkhead...

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HOW TO INSTALL CRACKEDBACK'S HEADLIGHT HARNESS

Well here we go. It's not "quite finished, but it;s installed and working. I just need to mount the relays and the little fuse boxes, zip a few zip ties in and done. Here we go. Of course, it goes without saying, doing any type of electrical work, disconnect the ground side of the battery...

www.forabodiesonly.com

There's also a pretty smokin deal from Toyota. Place an order for replacement 7" sealed beams on your older Landcruiser and get new Kiota H4 lamps with a relay harness. You'll probably have to do a litttle modification to the harness to adapt it for your A-body but its a great deal. Order just one, it comes with two lamps and two bulbs. You may want to upgrade the bulbs.

Sealed Beam Headlights

Interesting thread on another forum: It appears ordering part number 81110-60p70 from a Toyota dealership gets you two Japanese-made Koito 7" H4 headlamps plus wiring and a relay setup for around $20. It's sold as a conversion for older Land Cruisers. No idea on how their beam pattern compares.

www.forabodiesonly.com

If you have a local dealer, that will be the fastest. If you have to order, Lakeland Fla. has a good price but they are limited in how many they get in each order so don't be surprised if there is a few weeks delay in shipping out.

These relays get wired in at the headlight and the alternator (not the battery!) so has no impact on wrapping up your repairs and troubleshooting.

 

[nick0705]

Update: car wouldn’t start no volts were present at coil, ballast or ignition module. Re-inspected ignition harness found bare wire fixed wires also replace the distributor cap due to the coil post being worn out. Now have 4 volts at coil with key on and 11v cranking. Got engine to start but only by keep giving it gas or it dies the ammeter gauge went up to +40 is this a sign of a bad alternator ? Batt volts were at 12.5 now when cranking and messing with it all day down to 11 but can’t get it running again by giving it gas to see if it is charging at the batt from the alt. Seems have a few issues going on. I will recharge the batt again.

 

[67Dart273]

What you need.
1.....A manual/ good wiring diagram.
2.....You have got to learn to troubleshoot voltage drop, and follow a circuit path.
3......If you cannot, you should consider rounding up someone who can help locally with some electrical experience. Not necessarily Mopar, but it would help.

You need to either draw out or get into your mind the PATH and the circuit connection points of the ammeter / primary power circuit and the ignition switch as it feeds the ignition circuit.

THE MAIN drop points are the big red and big black ammeter bulkhead connector terminals, and the ignition feed bulkhead terminal. The big welded splice in the black ammeter wire is rare but can break. The ammeter connections look like **** and are suspect. The ignition switch connector and the switch itself.

 

[Mattax]

Got engine to start but only by keep giving it gas or it dies the ammeter gauge went up to +40 is this a sign of a bad alternator ?

I still think that before you hook up the battey cable it would be worth
.... Slow charging the battery on a charger.

There's two possibilities, and it could both.
1. The battery was low on charge. Even with the alternator regulated to 14-14.9 Volts, a very low battery will draw over 40 amps if the alternator can supply it. Once the engine is revving at 1500 rpm or higher, its going to be getting close to being near its rated capability.

2. The alternator output voltage is not being properly regulated. One reason could be the field wire returning to the regulator is grounding (shorted)
Another reason can be the sensing wire is reading low (diconnected , broken wire, or resistance in the supply lines). The resistance is why checking for voltage at key locations is important. When there is a more current (moving electrons) then any location where there is resistance is going to cause a drop in voltage. If the regulator 'sees' 13 volts when the alternator is producing at 15 Volts, then the regulator is sensing low voltage, and will continue to create a field until it sees the 14+ volts. That might mean the alternator is producing at 16 volts. The battery might be seeing 16 volts, or might be seeing 13 volts. it all depends on where the resistance is, and where the current is going.

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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how does it ground ??

Hi All, Just putting the 1970 Rally dash back together after fixing the gas gauge ... and trying to see a ground point to the chassis. Is it just the mounting screws ? Thanks

www.forabodiesonly.com

 

[nick0705]

There's two possibilities, and it could both.
1. The battery was low on charge. Even with the alternator regulated to 14-14.9 Volts, a very low battery will draw over 40 amps if the alternator can supply it. Once the engine is revving at 1500 rpm or higher, its going to be getting close to being near its rated capability.

2. The alternator output voltage is not being properly regulated. One reason could be the field wire returning to the regulator is grounding (shorted)
Another reason can be the sensing wire is reading low (diconnected , broken wire, or resistance in the supply lines). The resistance is why checking for voltage at key locations is important. When there is a more current (moving electrons) then any location where there is resistance is going to cause a drop in voltage. If the regulator 'sees' 13 volts when the alternator is producing at 15 Volts, then the regulator is sensing low voltage, and will continue to create a field until it sees the 14+ volts. That might mean the alternator is producing at 16 volts. The battery might be seeing 16 volts, or might be seeing 13 volts. it all depends on where the resistance is, and where the current is going.

http://[URL]https://www.forabodieso...rging-battery-with-alternator-warning.424783/

[/URL]

http://[URL]https://www.forabodiesonly.com/mopar/threads/how-does-it-ground.560443/post-1974664732

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I’m back working on the car it runs but I have a voltage issue still. With the key on not running I’m showing 12.5volts at the main ignition feed and the ammeter. My volt gauge is reading 10volts. Which is running the power of the cigarette lighter power. When running I’m showing almost 15 volts on the volt meter but when I put it in drive it drops to 10.5 volts. I’m coming to the realization I’m going to have to redue all the wiring in the dash the previous owner looks like they where just splicing stuff in.

 

[Mattax]

Going from 15ish to 10.5 V when placed in drive suggests an rpm drop sufficient that the alternator is no longer producing power.

 

[67Dart273]

Yup but that is pretty low. If you disconnected the alternator, and there isn't much for load, it should not go that low. Either you have some big drop in the harness or the battery is low on charge, low on capacity, or tired or defective. Measure at the battery and compare to the voltmeter in the car

 

[nick0705]

Need your guys opinion. So I started removing the in dash wiring harnesss to look deeper for broken wires. I have found a lot of wiring that looks just too bad for being 51 years old I have two options I need to ask yall. First I eventually want to build the engine up more and add a new alternator. Keeping that in mind. I see classic industries sells a new in dash same wire coloring harness for 800.00. Or there’s American Autowire that has the full car wiring for 1400 but looks a little more complicated. I am a disabled veteran I don’t have much money and my body isn’t the greatest to be doing too much work. I bought the car to enjoy and keep my mind clear. But seems that I didn’t know how bad the wiring was until I dug behind the dash. So if I go with the classic industries stock in dash new harness I also have a new engine harness that came with the car. If I do the American auto wire the full car will be re-wired kinda stuck has anyone replaced the in dash harness with the one I’m talking about ?

 

[nick0705]

Need your guys opinion. So I started removing the in dash wiring harnesss to look deeper for broken wires. I have found a lot of wiring that looks just too bad for being 51 years old I have two options I need to ask yall. First I eventually want to build the engine up more and add a new alternator. Keeping that in mind. I see classic industries sells a new in dash same wire coloring harness for 800.00. Or there’s American Autowire that has the full car wiring for 1400 but looks a little more complicated. I am a disabled veteran I don’t have much money and my body isn’t the greatest to be doing too much work. I bought the car to enjoy and keep my mind clear. But seems that I didn’t know how bad the wiring was until I dug behind the dash. So if I go with the classic industries stock in dash new harness I also have a new engine harness that came with the car. If I do the American auto wire the full car will be re-wired kinda stuck has anyone replaced the in dash harness with the one I’m talking about ?

Vans auto llc has the in dash harness as well it says brand M&H I don’t know what brand that classic industries is anyone know a cheaper site or are these the best two for replacement factory harnesses.

 

[Mattax]

M&H will be very close to original. Everything will be right length and plug in. My view of American Autowire is they are kits. Maybe a good route for a guy doing a late hemi engine swap with EFI.

I bought an M&H engine harness from Year One over 20 years ago. It was pretty good and has only needed a few repairs. When it did, I very glad I saved the original harness for reference and to baorrow a few parts from. An interior harness should last longer. Water leaks around the windshield, wipers or the vents are the main concerns with an interior electrics.

The only thing that would be a bonus (in my opinion) is if they have a harness option that bypasses the seat interlock. Unless you really want it, seems like a bunch of extra wires that are not needed.

 

[nick0705]

Thank you for your response does anyone know what this part is called that was mounted behind the dash with harnesses plugged into it ? See photos