71 RR with 383, AT. This car has been sitting for 3 years, finally got new tires, registration, new gas, etc. I drove it over 100 miles in the last 2 months. I take out the battery when not driving it.

Today, hook up the battery and it starts "crackling" like the the lights or on or something. Then I see the smoke from under the hood. Disconnect the battery. I thought a mouse may have chewed a wire or something. After fixing a few wires at the starter relay (hot side was fried), hooked up the battery again. No more crackling. Whew!

The passenger side park light is constantly on now, and I have no power to the coil. I can turn the motor over but no spark. Wires cooked, and from what I can see, some wires melted under the dash too.

So now my question. Why did it all of a sudden fry?

How do I fix it? I know very little about electrical so where do I start? harnesses will have to be replaced, but I seriously don't know where to start.

eightlitermopar

Another

I am guessing based on the car you called out and the pics.
Black wire burned out.
Traces back to the alt.
So your main power circuit feed ate itself.

Either your amp meter died, alterator died with a dead short, or that was melting all along from not being maintained/cleaned and finally burned through this last time.

the light and not being able to start are burned wiring or connections.

you need a new engine harness and dash harness if you can't trouble shoot the wiring yourself.

http://www.mymopar.com/index.php?pid=27

will give you the diagrams you need to see where the wiring goes and wire in new ones or pop out the harnesses and start again with new connectors.

somewhere in the main circuit from battery positive post to FL to bulkhead inside dash to ammeter to welded splice to bulkhead & out to alt there was a dead short to ground (plus from welded splice under dash it goes to the fuse box/steering col (ign sw)/headlight switch. everything is hot all the time like the wall sockets in your house which is why it smoked when you reinstalled the battery without turning anything on. it smoked under the hood so start by tracing from the battery to the firewall & see if you can decipher where/how it got shorted to ground. NAPA has new brass "Packard 56 type" 1/4" male/female terminals for 99 cents ea (725147/725145) tho with the bulkhead damage you may have to run em straight thru. I think you can have someone replace the damaged circuits but first we gotta find that dead short.

Thanks for the replies. The starter relay "hot" wire was the one that was completely fried/melted. My original theory was a rodent had been chewing on the wires which caused them to short?

But it's impossible to tell now because its melted. Other than that, are there common culprits to check first? As mentioned, the alternator or something like that?

I would hate to go through all this and just fry my next fixed (or replaced) harness.

thanks again!

eightlitermopar

that is a strange one as the main circuit from batt to SR/SR to starter/SR to bulkhead are large wires & I wouldn't think a rodent would chew thru something that large but I dont know animals so I am speculating & if it chewed thru & severed a wire then that hot end would have to fall down & make contact with ground to effect a dead short. I'm thinking more a mechanical shift of something that grounded. However my new therapy cat that I adopted from CL, within a week it chewed thru the ph cord (a real thin one) & the next day it was relocated to the Humane Society.

most of the major pieces can be taken out and tested at the parts store.

as for the rest, I would guess a test light to the wiring.

wire up the ground to the battery like normal but leave the hot off.

then probe each line with a test light hooked to the pos of the battery.

if it lights up something on the other end is grounded.
Just have to find what it is.
The wiring diagram should help figure that out.

That's the alt wire running to ammeter. TIpical Mopar failure due the low output alts used from factory ( believe it or not ) which overheats the contacts ( unable to hold the extra load ) when reving up the engine... all along these years up to the final failure.

Check this thread.

How it works the Charging circuit system and how to upgrade or fix

thanks! this gives me some information I was not aware of. Given The fried bulkhead, I was wondering if my starter relay wire was bad as stated -OR- something under the dash causing the problem; ie ammeter

From what I can see, some wires under the dash appear melted too. My theory now is some melted wires that are now touching so the hot wire is now feeding a park/turn light instead of my coil.

First step today would be to remove the steering column and take out the instrument cluster to gain better access and see what I am doing. Does this sound like a good starting point in my position?

I may be able to repair some wires instead of buying a whole new harness, but we will see once I get in there.

Thanks!

eightlitermopar

so take your cell phone and record the hold downs as you remove it.
The routing is a bit odd and tight in places for the few I have pulled.
I would start with the bulkhead connector and work my way back. Start in the engine compartment and pull those on that side.
the whole box comes out from the passenger compartment side and then you have to start finding where it is held down from there.

Unfortunatly the underdash is going to go to a lot of things, vs the engine side one that has only a few items per plug.

So just to clarify, starting under the dash is the best place to start? I figure removing the steering column and instrument cluster will make a difficult task a little bit easier?

I am doing this in baby steps because its my first time and I don't want to screw anything up more than it already is.

Having a 71, I can say it would be easer pulling the column and seats, rotating the dash down so you can get to everything and put the new back where the old was. Be sure to check the wires that run through the column cause that is where the voltage regulator gets its signal from. Be sure to buy a can of Dioxit 5 to clean all the terminals that get reused.

Thanks for the suggestion, I did just that. I am not as small as I used to be 20 years ago when I bought this car in high school.

Sure enough, fried wires to ammeter. I will try to cut out the melted portion and rewrap, but if not I will just get a whole new harness and go from there. If there is another way to save this harness, I am open to suggestions. Thanks!

I was just commenting on how to start on the harness.
not the procedure to get to it.
I would listen to the poster above that owns one.

Though I personally would try to pull as little as possible as I know how tough it is to get it back.

But yes you are right, it is much easier if you can see instead of working by braile. With all the dash compoents removed you can see where the routing is and what needs to be un twisted etc..

right at the back of the cluster

ugh.
till you peel it apart, no way to know how much is melted together.

I had one issue that burned 3 inches of insulation both ways and vaporize about an inch of copper. 10 gauge wire.

you can't trust you got it with just the ends as much as that tape burned away.

once you get deeper into it, you may find most of the insulation is damaged on the remaning line and you can't pull it apart.

you could still salvage the harness if you want to take the time to rewire it.

cost vs time is where you are at now.

looks like a dash harness is around 500 depending on rally gauges or not.

Also, on a 71, the gauges are almost impossible to get to with the dash installed, so if anything needs done to them, do it now. I would buy one of the electronic voltage limiters from Real Time co, and replace the old one, cause if it goes bad it can stick either open, or closed, if it sticks open that will fry the gauges. On the harness, buy one from Year One cause they are the best. If you need any more help, just holler.

Keep digging (unwrapping) till you find out where it dead shorted to ground.

Some great advice for tracing.

I find it much easier to work with pictures and diagrams.
Feel free to download any of the diagrams off this page as starting points.
http://www.heritech.org/cuda/Charge.html
Modify it to match your 71, or do your own from scratch using screen shots from the shop manual. You can see I did that for my '67 (at bottom of page linked).
MS Paint will do pretty much everything needed.

Why?
This will be easier to figure once you've ID each damaged wire.
The wire that should have protected all the rest from too much current from the battery is the fusible link.

A rodent chewing partially through the Battery + to Relay would reduce its current carrying capicity but wouldn't explain the damage at the bulkhead and behind the dash. A connection to ground (such as bare wire touching the body due to chafed insulation) would draw as much as the battery can deliver.

If you're going to replace individual wire yourself, you'll need:
Packard 56 terminals for a range of wire sizes.
Small flat terminal removal tool makes it easier.
A good crimper - Compound action and exact fit makes it easier.
A good wire stripper.
Electrical contact cleaner.
Correct wrap - or the wrap of your preference.
Wire with the correct insulation. I like to go to the marine supply because they stock many different colors and sizes that can be purchased by the foot. Also know that most wire at auto parts stores are for chassis. Engine compartment insulation has better oil and heat resistance.

That's all for later, if you go that route.

If he still has the fuse link, this failure is not a short, because fuse link should blown.

ALTHOUGHT, wiring looks fried like a short and not overheated! Interesting!

Amm studs look healthy


Wondering what it was the reading on ammeter when it happened!