1968 Charger Wiring Meltdown

[yamanut1970]

Hi all.

I had a wiring meltdown in my Charger late in the summer. I'm waiting for my M-H wiring harness from Year One.

Still not 100% sure how if happened but I have a theory and wanted to see if anyone thinks it's possible.

I put a new carb with an electric choke on this summer. A buddy stole power for it from the connector on the ballast resistor on the firewall. That wire, which loops to the voltage regulator, through the engine harness along the firewall, through the bulkhead connector and right to the back of the ignition switch, had every bit of insulation off of it. It destroyed the harness and bulkhead connector block. When I saw the smoke and popped the hood, the wire from the ballast resistor to the electric choke was laying on the intake (there was no protective rubber boot over the end to prevent it from grounding out) The connector is quite tight if I slide it on now so I don't think it shook loose but was maybe not pushed all the way on.

What I'm wondering is, if the connector was not pushed on the electric choke all the way and fell off and grounded on the intake, could it have caused what I have described to melt?

The car just shut off while I was driving and smoke started to come out from under the hood. I pulled over and popped the hood and could see the wire smoking. It worked it's way back through the firewall and smoke started coming out of the dash. I then realised I hadn't turned the key to the off position when I pulled over but only threw it in park because the engine had died. As soon as I turned the key to the off position, my own personal Chernyobl came to an end.

Anyone?

 

[Hemi Rebel]

Yes, if the power wire to the choke shorted on the intake it would let the smoke out. Like it did. Should be a fuse on the circuit somewhere. Might wanna check that. It should have blown

 

[SlinktRR]

Yes, if the power wire to the choke shorted on the intake it would let the smoke out. Like it did. Should be a fuse on the circuit somewhere. Might wanna check that. It should have blown

Been there. Don't wire the choke to the ballast, go to another keyed circuit or it will short on headers, intake, whatever. It can also torch your gauges. wire an inline fuse if you can't run through the fuse panel. I disable the choke in the summer anyways.

What blew me away was the speed with which my meltdown happened, instant. Change everything because there is no telling how far the damage goes. I was lucky the direct short melted the wire through and killed the engine, else.. Well I'd rather not think about it!

 

[440roadrunner]

Unfortunately on the older cars, the only protection for the ignition circuit is the main fuse link, and since the ignition wiring is much smaller, that is really no protection at all.

If you don't need "resto purity" there are things you can do. One is to use a Bosch style relay to run the ignition, other relays to run other loads. Be careful you do not use too small fuses

Two circuits you do NOT want failing on you "when driving" as in heavy traffic and at night, are the headlights and the ignition.

 

[mopar vince]

bummer - but common problem

You most likely had resistance at the bulkhead connector or a failure of the ampere gauge in the dash.
A lot of the fusible links in these cars that were factory installed in the engine compartment at the bulk head connector to prevent an incident in the dash like you had have been "used".
Usually someone would "fix" this by just drilling through the bulkhead connector and running a wire straight through to power the car back up.
Unfortunately this takes away the safety factor should there ever be another high amp draw anywhere in the system again from a grounded out wire or bad connection resistance.
Read this: http://www.madelectrical.com/electricaltech/amp-gauges.shtml

 

[440roadrunner]

You most likely had resistance at the bulkhead connector or a failure of the ampere gauge in the dash.
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Disagree in this case. This sounds exactly like what someone described.......a short in the added wiring to ground.

 

[yamanut1970]

Thanks Vince. The gauges are all aftermarket (voltage gauge) As I mentioned, the only wire melted under the dash is the one from the bulkhead connector to the ignition. I have heard that the old amp meters being problematic!

You most likely had resistance at the bulkhead connector or a failure of the ampere gauge in the dash.
A lot of the fusible links in these cars that were factory installed in the engine compartment at the bulk head connector to prevent an incident in the dash like you had have been "used".
Usually someone would "fix" this by just drilling through the bulkhead connector and running a wire straight through to power the car back up.
Unfortunately this takes away the safety factor should there ever be another high amp draw anywhere in the system again from a grounded out wire or bad connection resistance.
Read this: http://www.madelectrical.com/electricaltech/amp-gauges.shtml

 

[SlinktRR]

You most likely had resistance at the bulkhead connector or a failure of the ampere gauge in the dash.
A lot of the fusible links in these cars that were factory installed in the engine compartment at the bulk head connector to prevent an incident in the dash like you had have been "used".
Usually someone would "fix" this by just drilling through the bulkhead connector and running a wire straight through to power the car back up.
Unfortunately this takes away the safety factor should there ever be another high amp draw anywhere in the system again from a ground wire or bad connection resistance.
Read this: http://www.madelectrical.com/electricaltech/amp-gauges.shtml

The previous owner of my car took this issue seriously and drilled the bulkhead for a 10gauge wire (as indicated by MAD) and put in a 30amp relay on the main ignition with soldered connections, using keyed ignition as the control circuit. All connections were soldered.. but not insulated. A soldered connection touched ground and torched the control circuit all the way to the underdash connector. The meltdown caused some collateral damage in the harness that I had to rewire and crimp just to get the car to start again. I replaced the relay with a new one, it works but for the long term I need to redo the harness or replace with M&H.

Relays are a good solution. I have been debating whether I should redo the previous owners work using relays and drilled connector, or just go back to OEM setup (M&H harnesses) with bulkhead and blade connectors. I figure if I use dielectric grease and keep things clean and dry it should be ok. Maybe put in an inline fuse to supplement the fusible link?

 

[dodge68charger]

Can the choke be wired to the blue wire that goes to the coil from the ballast resistor if the ballast resistor is bypassed?

 

[bigmanjbmopar]

Not recommended, you need a clean, dedicated wire from the "key on" source I would run my own, you can use as small as 16 awg wire stranded I would tap it into the Q2A-14BK wire that is for all the accessories "key on" source from the fuse box.

For the diagrams see here- http://www.forbbodiesonly.com/mopar...agram-Sticky-Please&p=910344456#post910344456

Can the choke be wired to the blue wire that goes to the coil from the ballast resistor if the ballast resistor is bypassed?