Fusible link wire plastic connecter melted that plugs into the main red wire , located drivers side fender harness on 70 cuda ? Wire connection was tight together, as were both connectors tight on the wires. With the key in forword run position (but no lights or acc on)blue wire fusible link side connecter is very hot and when I pull them appart there is a large spark.
Please help me troubleshoot. History; after a short drive home in a little rain yesterday with road lamps on for others to see me, I got home Ok but when I lifted the hood to see my engine bay was mostly dry I found the Fusible link wire black plastic connecter melted where it plugs into the main hot red wire feed that goes back to firewall bulk head area. Note When I turn the key forword to the run position (no lights or no road lamps on yet)this fitting get burning hot in 1 min, and with key in back acc position no heating until lights turned on. Been driving this cuda for several years with out any electrical problems. It has fairly new (8yr old) repro engine & dash harness. Please help me toubleshoot , I have a electricical multi-meter , so where should I start ?
thanks Doug. Please send help to my email if you have the time, dougandcindy@eastlink.ca

Its incredibaly common for the ammeter wire to short between the gauge and the bulkhead, often leading to a melted bulkhead connection at the firewall and causing other issues like your melted link. I'd start there. I'd end by replacing (again) the entire dash and engine bay harness with a new one from M&H (sold exclusively through Year one).

If you are going to end up by replacing the harness, I'd look into the one made by American Auto Wire. It uses factory Mopar connectors and has lot's of extra provisions for updating if you ever want to go that route. I'd ditch the ammeter and install a voltmeter. Lot's of info on how to do that. There wouldn't be lot's of info on how to do that if it wasn't a problem.

any tips on where to troubleshoot first/ logically, in case its only one wire or fitting grounding out, maybe that is repairable !
i.e. starting with areas that can be reached or seen without removing the rally cluster completely out or pulling the whole harness out ?
I am courious as to why in the key back aux position the wire doesn't get hot until I turn on a heavy user such as road lamps ? But with key in the run position it gets hot without anything turned on ?
thanks for the help, DOUG.

key on automatically supplys power to the coil/ignition system and charging.
so you are pulling a load whether you turned something on or not.

aux does not run power to those things.

OK thanks for that key position info.
Now does anyone have any basic steps what to check first, starting with areas easy to get access to look, or how to test ? thx Doug.

step by step is going to be hard.

so you still have power inside, just no charging.

I would bypass the bulkhead for now. run a 10 gauge from the back of the alt to the positive side of the battery.

that takes out the bulkhead and amp meter.

then fire it up and start checking voltages.

once you are sure nothing is out of whack there, then you can start checking what gave.

most likely 2 sources of problems.

1 the bulkhead connector itself.
the corrsion builds up there and causes heat and melting. shorts stuff out.

2 the amp meter as mentioned above.

you can pop the bulkhead connector and report back on what it looks like. green and melted guts means it was bad.

you can bypass the amp meter by putting all the wires on 1 post, but won't make a difference till you get power back through the bulkhead.

Andrewh, first thanks for your suggestions, In reference to your last post, YES I still have power inside and everywhere else ALSO has power OK too, and all electrical circuits are fully functional (yes, including the charging system which works OK). All gauges in the rally dash including the ampmeter appear to work normal. Lights work. Motor run & starts normal. So far I have found is the fusible link connnector get very hot when the engine is started, or if key is just turned the run position. I have a friend coming over Sat am to help me look at firewall area bulkhead, & ampmeter , then start try to check a section at a time ? I pulled my radio so we can get access to view the back side of the ampmeter an visually the wires look OK. thx for the help, I appreciate any other assistance, later DOUG.

It might simply be a bad connection for the fusible link. Like others in the original setup, it is 1/4" spade type and not real high capacity. I had the same problem on an E with re-pop harness after driving in the rain with lights and wipers.

The fix was a new section of fusible link. I connected it with soldered on eye ends joined with a 3/16 screw, lock washer and self locking nut. Belt and suspenders with some electrical tape for insulation. Trouble free since and no heating.

FYI my fusible link over heating problem appears to be the 16g link wire & connection. We replaced it with a test wire 1 size up 14g(just what I had on hand to use) with new fittings on each end, used fine emery paper to clean the downstream red 10g wire female connector where the link plugs into and the voltage drop across the test wire was ~80% less that of the hot orig fusible wire & the amp draw with engine run position only on dropped 1.5 amps, and with max load every elect curcuit on incl headlights & roads lights etc all on, the amps dropped 3+ from 26-27 down to 22-23 . And with max amp load now connector that got burning hot only gets warm, thanks to all for your suggestions, DOUG.