74 Duster Fusible Link

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MOPAR JIMMY

MOPAR JIMMY

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Hello everyone,
My name is Jimmy and I have a 74 Plymouth Duster and i'm having some issues with the fusible link smoking , burning up. From some of the videos on you tube and threads that i have read there seems to be am amp meter issues. Not counting the fusible link that was in the car when I bought it, 2 fusible links that i have replaced in the last 2 weeks have burnt up. I disconnected the wires on the amp meter from behind the cluster and used a nut and a bolt to connect them back together with electrical tape, found that info on a electrical web site called MAD enterprises. I also installed a new Valiant Scamp Duster Motor Fusible Link Wire Harness Plug just incase and after connecting it all 2 different times, the fusible link still smoked out. I also bought a starter relay motor but have not put that in as yet. Just ordered another fusible link from Classic Industries and waiting for it to arrive. I'm lost and could really use any help to figure this out. I thank everyone that takes the time to help me out with this issue and I hope I'm explaining all the right. Thank you again
Jimmy
 
Hi Jimmy. The first thing you need to do is STOP! Disconnect the battery if you haven't already and don't go any further until you find a wiring diagram for your car and engine before you do any further damage.

You are most likely scaring away the pros (I'm not one) that are here with your approach.
 
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Hello and thank you for your reply, yes first thing I did was disconnect the battery. Every time I tried to fix this, the battery was connect to see if I fixed it and disconnected again. I'm not a pro at this either but from what i have been reading and some videos I have watched, this AMP meter is a big problem. I'm trying not have to re wire the whole car because from what I can see everything else looks great, nothing burnt.
 
If you did the ammeter bypass and still blowing fusible links most likely the issue lies in either the battery/alternator or starting circuit. You'll need a wiring diagram and a multimeter to find the short.
 
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I have a multimeter I borrowed from my friend, going to try that this weekend. Getting a wiring diagram also. Very strange this is, the car was running great then I went to start it one day and all the lights inside the car went out . Tried to start it again and there was smoke coming from the bulk connector at the firewall and what smoked out was the fusible link.
 
You can try the 72 manual, hard to know exactly what the changes are, but it should be close enough for diag work if you're solid with electrical work.

Service Manuals – MyMopar

To follow up on your posts some.

1. Don't keep burning up fusible links, if you have to make a repair again consider an appropriately sized maxifuse, this way it's easy to replace if you pop one.
2. Fusible link comes off the battery post on the starter relay, goes through the bulkhead, through the amp meter and then to a junction that feeds a lot, all of the below is before you turn the key on.
  • Ignition
  • Battery feed side of fuse box (hazards, tail lights, dome light, lighter)
  • headlight switch
  • horn
Start with something simple, does it blow before you turn the key or after? Help narrow down where the short is.
 
Thanks for the reply, not very good with electrical unfortunately. Soon as I turned the key to the Auxiliary position is fried the fusible link. Lights were on inside the car right before. I have a new starter relay that i'm going to install as soon as the new Fusible link gets here.
 
Welcome to the forum! If the link goes that quick - as soon as you energize the accessory circuit as you said - there's a short in there possibly. You need a volt/ohm meter to properly find the problem. The starter relay state does NOT change when you turn the key to accessory. Wipers, heater fan, reverse lights and radio are all on the switched hot circuit.
 
Well if you're still working on this and want to solve this
a. post up
b. stop following the youtube video's and MAD @Woodys_Cuda and @TurboGLH were giving you good advice.
 
Seat belt buzzer and light won't go off This post has info for 74
Circuit diagram start about post 24 ignition switch 18 over B down Switch marked r ACC circuit 12 BK ,goes threw electrical connector ci 1, turns into Q 2 12 BK, goes to splice with V1 12 P to wind shield wiper motor. Q 2 12 BK goes on and ends in fuse block, feeds fuse 2,3 and 4. Any where along this circuit Q 2 12 BK shorted to ground including inside steering column, would blow fusible link
 
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Thank you everyone for posting, i'm going to dig more into it tomorrow using the info that was posted here. Thanks again.
 
If you're not great with electrical, do yourself a favor.

Print out the under hood and dash wiring harness pages, biggest you can make them. Get a highlighter and going between the two, highlight everywhere that gets power through the fusible link. Don't forget the power after the ign switch.

Once you've done that, start thinking of ways to isolate parts of the harness. Fuses that can be pulled, connectors that can be undone, etc

Set your meter to ohm, if it's a model that can beep when there's sub-one ohm, turn that on.

Unhook the bulkhead connector that has the fusible link.

Probe the body side of the bulkhead, in the fusible link port.

Other lead to the body, on a cleanish ground point.

If there's a short (and there is). You should see zero ohms, or like 0.2.

If shows open, double check that you're in the connector right, and then turn on the key.

Does the meter show a short?

Now you know if it's before or after the ign switch.

Once you know that, it's time to use that highlighted harness picture and start unhooking items.

ONE AT A TIME!!

Proceed until you find the short and fix it
 
Great advice.
The '74 diagrams requires some assembly.
The diagram here is redraw of the factory diagram but showing only the main circuits.
www.forabodiesonly.com

1974 Duster total electrical failure, followed by quick recovery.

Hi All: Just had this happen today. After shutting off my engine (225 auto), the entire car went completely dead. Nothing. Having seen this before on another Duster, I immediately located the main battery feed connector behind the brake booster. This is a heavy gauge red wire with a...
www.forabodiesonly.com www.forabodiesonly.com
Notice where the fusible link is.

If you had observed the ammeter before you disabled it, if it moved to max discharge as the link started to smoke, then the short is further downstream.
As noted above, the regular fuses would protect from a short downstream of them. In other words the fuse would blow before the link failed. So that narrows down the location of the short.

This next thread is an example of working with the '74 factory diagrams to track down the cause of a fuse blowing
www.forabodiesonly.com

Turn signals not working, blowing fuse

1973 Dart headlights work Brake lights work Hazards work, including indicator All bulbs are functional turn signal switch gives me nothing, no lights, no clicking, no indicator UPDATE: Fuse blows as soon as the key is turned on. just looking for guidance as to where I should continue diagnosis
www.forabodiesonly.com www.forabodiesonly.com
Once he systematically disconnected the connectors, the branch with the short was then identified.

Note: If your car has an electric defrost grid on the rear window, it has a slightly different main wiring arrangement.
 
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