Darn Electrical Bugs

[HoffMopars]

Hi, I've been getting my rig ready for the summer, been working on it when possible on the weekends. Last owner had 2" lowering spindles and blocks in the rear, I took the blocks out and got a set of factory front spindles, rough alignment and planned on driving it somewhere near by to have done professionally. Running bigger tires on it as well now, threw an alternator at the thing since it didn't charge at all last summer, probably should've just checked the rig out a bit more instead of tossing parts at it.

And that's where I find myself at now, digging through someone else's wiring, loads of fun. The two pictures attached are where I'm assuming something got hot and melted through, there's a newer crimp on the two wires. The one that got hot was the two wires that combine to feed the cab power. The battery wire on the alternator has no back feeding from the battery, and only gives off 3 volts when running. When running the exciter wire shows no volts, not a great guy with wiring. Thanks for taking the time to read all this, hope I can get it figured out and running reliably for the whole summer.

 

[LS&S]

Hi, I've been getting my rig ready for the summer, been working on it when possible on the weekends. Last owner had 2" lowering spindles and blocks in the rear, I took the blocks out and got a set of factory front spindles, rough alignment and planned on driving it somewhere near by to have done professionally. Running bigger tires on it as well now, threw an alternator at the thing since it didn't charge at all last summer, probably should've just checked the rig out a bit more instead of tossing parts at it.

And that's where I find myself at now, digging through someone else's wiring, loads of fun. The two pictures attached are where I'm assuming something got hot and melted through, there's a newer crimp on the two wires. The one that got hot was the two wires that combine to feed the cab power. The battery wire on the alternator has no back feeding from the battery, and only gives off 3 volts when running. When running the exciter wire shows no volts, not a great guy with wiring. Thanks for taking the time to read all this, hope I can get it figured out and running reliably for the whole summer.

View attachment 1716412743View attachment 1716412744View attachment 1716412745

On the wire that got hot, I'd bypass the original connector with a bullet connector like this link
https://www.homedepot.com/pep/Gardn...aah2NV1nrsxxL6OfR3kaAuN2EALw_wcB&gclsrc=aw.ds

 

[Mattax]

Thanks for taking the time to read all this,

That wasn't too bad.
It will be your turn next. LOL

And that's where I find myself at now, digging through someone else's wiring, loads of fun. The two pictures attached are where I'm assuming something got hot and melted through, there's a newer crimp on the two wires.

My suggestion.
First, learn how the system is supposed to work.
Second, identify any factory options and all equipment alternations by previous owners.
Use the shop manual for your year and model to identify the circuit positions in the multi-connector.
Then you can figure out what was modified, and maybe why.
Knowing all the above you can come up with a repair plan that will be reliable.

The battery wire on the alternator has no back feeding from the battery, and only gives off 3 volts when running.

The terminal on the alternator marked "Batt" feeds the main junction.
Current should never flow into it. It can happen when things go really wrong... Lets not go there right now unless there is evidence pointing that way.

 

[Mattax]

First, learn how the system is supposed to work.

The car has two power sources; battery and alternator.
Each has a wire that connects to the main circuits at a welded junction.
This junction is hidden in the harness.
Power goes to the junction and then can continue on. All of the wires attached at this junction are attached to the battery positive, so they are always hot.
The main feeds go to:
1. Fuses that are always hot. (wire Q3)
2. Headlight switch for headlights (wire L1)
3. Key switch. (wire J1)

Power to the horn is an exception. In '66 its connected at the starter relay. In 1967 its attached at the alternator's output terminal.

The ammeter shows whether current is flowing in or out of the battery.
The battery can supply power at only at 12.8 Volts in the best of situations.
The alternator can supply power at 14 volts give or take a little.
So between the two possibilites, electricity always flows from the higher voltage source, as long as it has enough power and the resistance is about equal.

After starting the current should flow from the alternator to the battery as well as the ignition and field.

After a few minutes the battery should be recharged.

So that's how it works.

Voltage differences reveal a loss of energy in the path the electrons are moving.
Here is an illustration of voltages measured in a '66 with the key in run, engine off.

This narrowed down the likely problem locations
There's no loss in voltage from the ammeter to the regulator.
There was a slight loss between the starter relay and the ammeter, and there was no connection in the alternater feed to the main junction.
Finally the regulator should have been full fielding because the voltage was low. So something has probably failed in the regulator. His is transistorized so it can't be checked visually. An electro-mechanical one can be examined for issues.

 

[Mattax]

How the alternator and regulator work

Identifying Chrysler Alternators (1960-1976)

Roundback and Squareback refer to the style of housing. Roundback through model year 1969. Roundback for model years 1970-71 usually has a slightly different rear housing Squareback Revised Squareback Is most easily differentiated by the thin middle between the housings. Overall these...

www.forabodiesonly.com

www.mymopar.com for scanned service manuals, parts books, and Master Tech conference. The factory service manual has the most accurate wiring diagrams generally available.
Master Technician Service Conference - Chrysler's Training for Mechanics The on-line Imperial Club has a better index of the Tech Conference.

The 1970 Hamtramck Registry Library Page Has Service Bulletins (updates to the parts and service books) and Sales Information (such as options for buyers)