Harness compatibility help

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Dk.03

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So I recently bought a full body harness that was for a 1974 duster and I wanna use it in place of my butchered 1973 duster wiring harness. I believe the dash harness is compatible because it looks extremely similar to the harness that’s already in the car. My problem comes when I was comparing the engine bay harnesses. Looks to be a noticiable difference. I understand it’s a different year harness for a different car and it should be different. I just wanna know if there is specific things I should be looking out for, if anyone who has done this before can help it would be appreciated. I’ve never done a harness before and I’m trying to do everything right the first time.

1973 duster, automatic with 360 la small block, I don’t know if having this matters or not.
Idk what the 1974 duster was
 
You need to get BOTH manuals and an ohmeter/ continuity tester and do a wire by wire comparison. One huge and annoying difference is the 1974 ONLY seat belt starter interlock.

IF YOU DO NOT HAVE a 74 manual, SEND ME A PM I can send you a digital copy for a little bit of shipping and you send me a USB mem stick
 
I’ll try and find the manual online but if I can’t I’ll pm you. Also what do you mean the seat belt started interlock? Does this stop the car from starting and is their a way to bypass ?
67Dart273 said:
You need to get BOTH manuals and an ohmeter/ continuity tester and do a wire by wire comparison. One huge and annoying difference is the 1974 ONLY seat belt starter interlock.

IF YOU DO NOT HAVE a 74 manual, SEND ME A PM I can send you a digital copy for a little bit of shipping and you send me a USB mem stick
Click to expand...
 
www.forabodiesonly.com

Looking for 1974 Plymouth Duster wiring diagram

Can anyone help? Found the valiant one at mymopar but not really the same. Thank you.
www.forabodiesonly.com www.forabodiesonly.com

You can dig around the ' net and compare photos and diagrams of other standard '73 and '74
for example
www.forabodiesonly.com

Turn signals not working, blowing fuse

Don't concentrate on the turn signals!!! Find out what all is on that fuse, someone posted a chart earlier......... Radio Back up lights Dash mounted reverse indicator (if used) Stop lamps Turn signals. 1...Pull the flasher 2...Remove left kick panel and separate the connector to the rear...
www.forabodiesonly.com www.forabodiesonly.com

Before you get too deep:
If your car was equiped with a rear window defrost grid, then it got a modified harness.
If your car was equiped with a 'fleet' alternator,but no rear defrost grid, then it got a different modified harness.
 
Let me add that the diagrams are useful but you will probably be best off by laying out both harnesses on a bench.
Label the connections and then compare.
Examples.
www.forabodiesonly.com

WIRING NIGHTMARE

I'm gonna start rewiring my 73 Scamp just under the hood for now, from the fire wall forward. Everything works just fine but by the looks of it something will short out soon and can't afford a new wiring harness I think the price was 800** for the kit so I'm gonna try to build my own harness. It...
www.forabodiesonly.com www.forabodiesonly.com

Note that my statement in that thread about Packard 56 connectors is not entirely correct.
Most, but not all, of the connectors are similar to a Packard 58.

Basic harness strategy was to bundle the wires for secure attachment with just enough stress relief. Pay attention to how the harnesses are routed and supported.
The wiring strategy is helpful to understand why certain items connect to the loactions they do.
 
Dk.03 said:
I’ll try and find the manual online but if I can’t I’ll pm you. Also what do you mean the seat belt started interlock? Does this stop the car from starting and is their a way to bypass ?
Click to expand...
Yes. The seat belt interlock module was 74 ONLY and interrupted the yellow start wire under some conditions. You could rewire it, but there is a fair amount of more wiring added for that stupid seat belt stuff
 
Mattax said:
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You can dig around the ' net and compare photos and diagrams of other standard '73 and '74
for example
[/URL]

Before you get too deep:
If your car was equiped with a rear window defrost grid, then it got a modified harness.
If your car was equiped with a 'fleet' alternator,but no rear defrost grid, then it got a different modified harness.
Click to expand...
Can you explain what a fleet alternator is?
 
Dk.03 said:
Can you explain what a fleet alternator is?
Click to expand...
A heavy duty option mostly seen on fleet purchases, for example police or taxi. The exact model alternator varied from year to year and application.
Alternator output was split on the engine side of the firewall. One feed going to the battery via the ammeter through a grommet in the firewall. The other feed going to the everything else.

A big clue will the use of a grommet for wires going through the firewall to the ammeter.
Here's an example on an export Swiss '74.
1688405117899.png



Photos in the link below of the heavy duty version seen with the rear defrost grid.
In this version, the alternator output splits at the ammeter connection.
1688405958168.png

www.forabodiesonly.com

How rare is electric rear defrost?

Not an accurate one. I've had acouple good offers for the switch. But wanna give someone a chance to buy it all complete first before I separate it all out. Depending what shipping ends up being, I’d be interested in the whole setup.
www.forabodiesonly.com www.forabodiesonly.com
 
Mattax said:
A heavy duty option mostly seen on fleet purchases, for example police or taxi. The exact model alternator varied from year to year and application.
Alternator output was split on the engine side of the firewall. One feed going to the battery via the ammeter through a grommet in the firewall. The other feed going to the everything else.

A big clue will the use of a grommet for wires going through the firewall to the ammeter.
Here's an example on an export Swiss '74.
View attachment 1716109891


Photos in the link below of the heavy duty version seen with the rear defrost grid.
In this version, the alternator output splits at the ammeter connection.
View attachment 1716109892
[/URL][/URL]
Click to expand...
So the alternator wiring that is on the duster right now, it goes straight to a connector along with the other 2 wires. The 74 duster harness has a thick black wire which goes into its own connector , like how the picture looks, and the other 2 go to a connector with additional wires. Also my duster doesn’t have rear defrost.

EEA77D97-AF6A-4838-AB2B-4B45CD33DA66.png
 
"Fleet" is police, taxi, fleet, optional 65A alternator. There is a LOT of discussion on this board and others about bulkhead connector/ ammeter wiring failures, most particularly, with larger alternators, and the factory optional 65 alternator is somewhat proof that Ma knew this was a problem. In effect it is a form of bulkhead connector bypass, as the terminals in them are limited for current

Also read this:



You don't have to do this in this way, and if yours is in good shape you may not need to, but kit is food for thought
 
67Dart273 said:
"Fleet" is police, taxi, fleet, optional 65A alternator. There is a LOT of discussion on this board and others about bulkhead connector/ ammeter wiring failures, most particularly, with larger alternators, and the factory optional 65 alternator is somewhat proof that Ma knew this was a problem. In effect it is a form of bulkhead connector bypass, as the terminals in them are limited for current

Also read this:



You don't have to do this in this way, and if yours is in good shape you may not need to, but kit is food for thought
Click to expand...

was it a mistake you sending a video about a windmill demolition?
 
Dk.03 said:
Also my duster doesn’t have rear defrost.
Click to expand...
if it doesn't have redefrost and there isn't a grommet with 12 ga or larger wires as shown in the photos above, then it was a standard harness.

Dk.03 said:
So the alternator wiring that is on the duster right now, it goes straight to a connector along with the other 2 wires.
Click to expand...

Dk.03 said:
The 74 duster harness has a thick black wire which goes into its own connector ,
Click to expand...

Dk.03 said:
like how the picture looks, and the other 2 go to a connector with additional wires.
Click to expand...

OK. I can't see any details in the photo. The Forum is set up for horizontal viewing. There will be less shrinkage with horizonatl photos. Still will be limited in pixels to 800 wide or something like that.

If I understand correctly:
1973 Harness on the car.
The alternator output wire, and the field wires, all go to an engine bay connector. That was done for several years. Reportedly to easy manufacturing. Connections there can be problematic. Especially if , as may be in this case, the wires are hanging free with no support. Worst if over the exhaust.

1974 harness.
Alternator output wire goes to a seperate connector.
When you note differences like that, that's when it time to refer to the diagrams in the shop manuals.


Side note: Fat wire, small wire, and so forth are the begining of the learning curve. Its also pretty hard to translate with any certainty. In this case, the alternator, its not an problem. But all these wires have names and functions which will be very helpful when comparing between the two harnesses.

The heavy black wire is alternator output. Chrysler always labled it R6 on the drawings. R for Alernator.
The blue wire is a segment of the run circuit. It primarily supplies power to the ignition and the alternator's rotor.
The green wire connects to the voltage regulator and controls current allowed through the rotor.
 
Last edited:
Mattax said:
1973 Harness on the car.
The alternator output wire, and the field wires, all go to an engine bay connector. That was done for several years. Reportedly to easy manufacturing. Connections there can be problematic. Especially if , as may be in this case, the wires are hanging free with no support. Worst if over the exhaust.
Click to expand...
From the '73 service manual. CE = Connector Engine Comparment
1688411499876.png

R6 12 BK = Alternator wire 6, 12 gage, Black (output wire) note this is always hot since it is joined to battery positive.
R3 18 DGN = Alternator wire 3, 18 gage, dark green (field control)
J2_ 18 DBL = Ignition Run, 18 gage, dark blue. (C, F and G are wire segments or branches)


Mattax said:
1974 harness.
Alternator output wire goes to a seperate connector.
When you note differences like that, that's when it time to refer to the diagrams in the shop manuals.
Click to expand...
From the '74 FSM.
1688411872192.png


So yes the connections are different. Since you have both halves of the connector, maybe it doesn't matter.
 
i plan on sending some pictures of both harnesses some time this week into this forum just so anyone who wants to help can see the differences and everything like that. I do appreciate all the help that was already provided, it should help make things easier when putting the harness in.
 
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