a puff of smoke and now nothing 69 valiant electrical issue

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sketch

sketch

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so my son was taking off the dash (he had taken the ground wire off the battery, as told) and he was replacing light bulbs that were burned out on the instrument cluster. (we have only had the car for a month, its a project). He reassembled, put ground wire back on and it started to smoke near the fuse box (i think, i wasn't here and he was in front of car( He quickly removed ground wire) now, nothing. No lights, car dead. I checked and the battery is fine. Used a light meter and not one fuse lights up the meter. Two questions:
1. what do you think happened?
2. How do i fix this? is it a simple (swap the fuse box), or am i looking at a new wiring harness?
 
the ammeter wires have to be removed to remove the cluster. MOST likely if that was not done one of those 2 main wires got shorted. that then fried the fusaable link under the hood near the bulkhead connectors typically lt blue.

other than that the main wires may have sorted under the dash and are now melted and separated.

hopefully it is a quick fix but most likely it is going to be a longhaul unwrapping harnesses and looking at a lot of wires. many times when a wire melts it melts the insulation off of some other wires next to it and they then come in contact with each other.
 
where are the ammeter wires? i think he took all the wires off except the main harness that goes into the dashboard. I don't see any melting. what does a fusable link look like (i am a picture guy) near the bulkhead connectors?
 
sketch said:
what does a fusable link look like (i am a picture guy) near the bulkhead connectors?
Click to expand...

as stated, lrobabky blue and is located in the engine compartment close to the bulkhead connector
 
sketch said:
where are the ammeter wires? i think he took all the wires off except the main harness that goes into the dashboard. I don't see any melting. what does a fusable link look like (i am a picture guy) near the bulkhead connectors?
Click to expand...
Here is a 71 B body fusable link but they are quite similar. I think my 66 is yellow.

fusable link.jpg
 
dartfreak75 said:
Always Always Always disconnect the battery connections when working on your car. Especially under the dash or anywhere there are wires.
Click to expand...
And always check for continuity (shorts) before you energize it. Just good practice.
 
sketch said:
where are the ammeter wires?
Click to expand...

Attached to the back of the ammeter
upload_2021-3-21_14-58-36.png

sketch said:
i think he took all the wires off except the main harness that goes into the dashboard.
Click to expand...

upload_2021-3-21_15-2-13.png

sketch said:
I don't see any melting
Click to expand...
Just because you do not see anything melted does not mean that something is not melted.
you might not see this with the covering still attached
upload_2021-3-21_15-4-21.png


sketch said:
what does a fusible link look like (i am a picture guy) near the bulkhead connectors?
Click to expand...
something like this
upload_2021-3-21_14-56-19.png
 
This may help locate the fusible link, pic of 69 Dart.
Its on drivers side firewall, Blue wire loop w/ tab. (Circled in yellow).
Screenshot_20210321-170535_Gallery.jpg
 
mymopar.com has free downloadable versions

or classiccarwiring.com
not your car but you get the picture
upload_2021-3-21_15-8-30.png
 
It happens. I grounded my watch band across the ammeter connectors. Of course the current melted it off my arm. Ya, I still have the scars! Unhook the battery dummy! :BangHead::BangHead::BangHead:

12461.poof.jpg
 
BTW the reason we are all pointing to the fusible link is that if it is popped (it is a sort of fuse) the car will be dead electrically.

AND the fusible link ONLY blows when there is a major short in the wiring.

so you have 2 issues to solve.

  1. what caused the short.
  2. what will need to be replaced to fix it.
then and only then put the battery back into the system
 
weird as he unhooked everything and rehooked everything with the battery unplugged. from looking at the picture, there was a positive and negative cable (red/ and black) that were screwed in. Could he have rehooked them backwards? if he did..then that would have gone to the fusable link? The light meter lit up when i checked for power to it with the link removed....
 
Dana67Dart said:
BTW the reason we are all pointing to the fusible link is that if it is popped (it is a sort of fuse) the car will be dead electrically. This is the case...totally dead.

AND the fusible link ONLY blows when there is a major short in the wiring.

so you have 2 issues to solve.

  1. what caused the short.
  2. what will need to be replaced to fix it.
then and only then put the battery back into the system
Click to expand...
 
When I'm doing any electrical work, I dis connect BOTH terminals at the battery. That way I'm for sure nothing will get shorted.
 
sketch said:
weird as he unhooked everything and rehooked everything with the battery unplugged. from looking at the picture, there was a positive and negative cable (red/ and black) that were screwed in. Could he have rehooked them backwards?
Click to expand...

if he reversed the wires only thing that would have happened is the ammeter would read backwards ( show charge when it is discharging etc.)

you can even connect the ammeter wires together and the only thing that woule happen is the ammeter would not read at all. ( ammeters are in series with the flow of electricity)


sketch said:
if he did..then that would have gone to the fusible link?
Click to expand...

not sure what you are asking / stating
sketch said:
The light meter lit up when i checked for power to it with the link removed....
Click to expand...

with what link removed? did you re hook up the battery? (dangerous at this point)
Where were you checking power?


a likely cause of a short is a pinched wire somewhere when he reassembled things.
PHOTOS are the best way to help us help you.
 
I thought he was talking about reversing the BATTERY cables. That would for sure cause "smoke and fire."

The MAD Electrical page has a simplified main power distro diagram. It should give a clear picture of the basics of the main power system

Catalog

amp-ga18.jpg
 
67Dart273 said:
I thought he was talking about reversing the BATTERY cables. That would for sure cause "smoke and fire."

The MAD Electrical page has a simplified main power distro diagram. It should give a clear picture of the basics of the main power system

Catalog

View attachment 1715711609
Click to expand...
He connected the hot ammeter wire to a connector nut. Not the bolt he took it off of. I’ll post picture shortly.
 
67Dart273 said:
I thought he was talking about reversing the BATTERY cables. That would for sure cause "smoke and fire."
Click to expand...
not necessarily... positive ground! maybe the radio would have an issue and the heater fan would spin backward! but I bet everything else would work as long as it was still using the old mechanical electronics like VR etc.

My grandfather had an old amplifier for a PA system that was positive ground. just don't set it on the metal of the car. ( it was a 12V powered system)
 
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