Fried Blue Fld wire from Alternator

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unclepunchy

unclepunchy

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Hi guys, 73 Duster 340, 4speed.

New 60amp Wilson reman Alternator. Turned on ignition and fried the blue field wire back to the 3 way split by the bulkhead. It looks like where it stops.

Did I get the wrong alternator or is it something to do with the spade connections?

668477DD-416F-4E41-A06B-C8190BC06201.jpeg


00D4492A-E0EA-4CEF-9909-4DDE4E63766E.jpeg
 
Does the top field terminal have an isolator on it? If so, I would take it back to the store, and have it tested.
 
With your alternator as it is in your photo.

Measure resistance from one field terminal to the alternator housing.

Then do the same for the other.

There should not be and connectivity from either terminal to the housing.
Most meters will read OL meaning there is no connection. If it reads 1 to 4 ohms there is a shorted terminal.


If there is, either you ordered an alternator for an earlier year or they mis labeled the one you got

OR

It is defective.



The square back alternator can be Iinternally wired like a round back which would have one of the two field terminals grounded to the housing.

regardless it looks like the blue wire was grounded at or near the alternator.


I looked at your photo again...

5 bucks say you will find a direct short to ground on the terminal circled.

Screenshot_20230729-171348.png



See post 10
New alternator, not charging

I'm betting that alternator is wired ( by the circled terminal) as a pre electronic, single field wire alternator.
 
Last edited:
Both field wires should be off from the terminals on the alternator just like in your photo

There is no need to have the car on.
 
Are you testing the terminals on the alternator or the wires.

This is what you got?
Screenshot_20230729-171348~2.png
 
Just of S&Gs. What's the resistance of the ohmmeter just touching the leads together?

It looks to me like they own you a new harness.
Good luck with that.

You had the bad luck of connecting the ignition wire to the grounded brush.
If you had connected the J2 wire to the insulated brush all that would have happened is overcharging and maybe burning some things out.

This is a constant problem with rebuilds these days.
Discussed in a few posts here: Identifying Chrysler Alternators (1960-1976)

And if that's a revised squareback, do yourself a favor and get something different.
if its a regular squareback, remove the brushes and measure the resistance between the slip rings.
If its in spec, buy some brush insulators and insulated washers and you can use it.
 
Thanks Mattax, if I can return this what would you guys recommend as a replacement so I don't have to piss around with this again.

Also. Is it okay I am using a 73 style VR? The 383 is from a 69 Charger.
 
If this is a single field style alt, what single wire would a guy use to connect to it, the green or the blue? And to which terminal?
 
Mattax said:
Just of S&Gs. What's the resistance of the ohmmeter just touching the leads together?

It looks to me like they own you a new harness.
Good luck with that.

You had the bad luck of connecting the ignition wire to the grounded brush.
If you had connected the J2 wire to the insulated brush all that would have happened is overcharging and maybe burning some things out.

This is a constant problem with rebuilds these days.
Discussed in a few posts here: Identifying Chrysler Alternators (1960-1976)

And if that's a revised squareback, do yourself a favor and get something different.
if its a regular squareback, remove the brushes and measure the resistance between the slip rings.
If its in spec, buy some brush insulators and insulated washers and you can use it.
Click to expand...

I touched the leads together and it’s around 1.6-1.8 ohms so that would negate the 1.6 reading on the blue fls terminal I guess. So does that mean that terminal is internally grounded?
 
unclepunchy said:
I touched the leads together and it’s around 1.6-1.8 ohms so that would negate the 1.6 reading on the blue fls terminal I guess. So does that mean that terminal is internally grounded?
Click to expand...
Looks like it is grounded through the mounting screw with no insulator on it.
 
Your car calls for a 2 field wire alt.

You could rewire the car to accept a 1 field wire VR and alternator.

You can not just use one of the 2 wires.

The 70 and newer VRs very the ground to change the field strength.

69 and older very the voltage to do the same.

You could replace the grounded field terminal with an insulated terminal.

And replace the melted blue wire.

This kit has both terminals in it, I don't know which one you need.




Screenshot_20230729-195347~2.png



OR

Assuming the seller told you what to order for your 73 then they goofed.

If you picked it out then you goofed.
 
unclepunchy said:
Like, can I just do this and then run a pre 70 VR with it? Image borrowed
Click to expand...
That is what the alternator is doing right now. No need to add the jumper.

I HIGHLY recommend you do it right and keep everything on the car as much the correct year as the car.

BTW just because the engine is a 60 something the rest of the car is 73 so ALWAYS order parts for a 73. If there are engine explicit parts check the same part for the engines age and the cars age and if the parts are different then ask here which to use.
 
unclepunchy said:
Thanks Mattax, if I can return this what would you guys recommend as a replacement so I don't have to piss around with this again.

Also. Is it okay I am using a 73 style VR? The 383 is from a 69 Charger
Click to expand...
Order a alternator for a 73.

The engine has no bearing on the VR or alternator you would use. Use the parts for the cars year.
 
Thank you Dana67Dart. I will keep all parts for a 73 in order.

Here is a photo of the Field terminal/brush I currently have.
F671C2EB-10B0-40E7-B955-0BF7C4B4E30E.jpeg
 
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