1970 300 Loss all electrical power

[Waggy]

I am still trying to find out why my 300 convertible loses all it's power at times. Sunday, I was driving along with overcast skies and the engine stopped. I coast to the side of the road and no lights, ignition, radio, or any other power but the top. I tried a jumper pack, disconnected and reconnected the battery (normally that has fixed the problem in the pass) and nothing. Got towed home, checked the battery and it was 12.27 v, but no power. Today (Tuesday), I went out to work on it and the power is back but the voltage is 11.36! I have done NOTHING!

Any ideas? Anyone know where I can get a new original wiring harness?

 

[Mr C]

How's your bulkhead connector?

 

[Snotty]

I had this happen on my Newport and the '70 Challenger I had 30 years ago. Both times it was a lose wire. For the Newport it was on the ballast resistor. For the Challenger is was the secondary ground wire on the positive battery cable.

 

[azblackhemi]

Fusible link?

 

[LocuMob]

I have the same issue from time to time on my Polara. I usually just undo the positive cable and that usually fixes it. I agree it's a bad wire/connection, as my harness has been unwrapped since my ownership, but I have another harness ready to go in. Check all the wires from the battery back to the firewall, should only take a few minutes.

 

[69monaco]

Same thing in the past with a 73 polara.........
What Scott says , wires from battery to firewall
Start the engine and check the wires , if your lucky the engine dies and you found the problem.......

 

[traintech55]

Check for a loose wire at the back of the ammeter.

 

[live4theking]

How's your bulkhead connector?

I have the same issue from time to time on my Polara. I usually just undo the positive cable and that usually fixes it. I agree it's a bad wire/connection, as my harness has been unwrapped since my ownership, but I have another harness ready to go in. Check all the wires from the battery back to the firewall, should only take a few minutes.

Check for a loose wire at the back of the ammeter.

All of what these guys said is good. Especially what Traintech said. This is the exact problem that I had last summer. Randomly I would loose all power, not even the dome light would work. 78Brougham helped me figure it out by reaching up under the dash and wiggling the wire harness. Check the power f from the battery back in to the car.

 

[Waggy]

Fusible link?

Good idea, but I by pass it when I had the problem and the by pass did not help.

 

[Waggy]

How's your bulkhead connector?

I have taken it apart and really cleaned it. I checked and rechecked the connectors when I put it back together. The problem I have now is before I did any of that the car "fixed" itself. I am going to move all the wires about to see if I can get the car to lose ALL power.

 

[Waggy]

If I knew what the part numbers for the wiring harness, I might just get a new one and install it. I know it is a lot of work, but I want to be able to trust the car and go on long drives!

 

[LocuMob]

If I knew what the part numbers for the wiring harness, I might just get a new one and install it. I know it is a lot of work, but I want to be able to trust the car and go on long drives!

You will have to find a good replacement, or have one made, sometimes using some of the old connectors from your old harness.

Evans working can help.

EvansWiring.com : Product Catalog

 

[Slantsix]

Not sure what has killed more Mopars, electrical fires or rust....

 

[traintech55]

Not sure what has killed more Mopars, electrical fires or rust....

Rust. Fords are the ones that like to burn up.

 

[Waggy]

It looks like the harnesses are Panel 2983267, Light & Engine 2983810 and Body 2983112 (convertible) and 2983113 rest. I can get the 2983113 but I have the convertible

 

[traintech55]

If you want new harnesses contact these guys. They have all the blueprints for Chrysler products.
Reproduction Wiring Harnesses for America's Muscle Cars
Many of us on the site have worked with them.

 

[live4theking]

Did you trace power into the passenger compartment? Where do you loose power at?

 

[Waggy]

Did you trace power into the passenger compartment? Where do you loose power at?

That is a hard one! I would say at the bulk head, but I do not have power anywhere in the car but the top switch and motor. I had the power on and I was working on the electric windows and I lost total power, I did not check the top. I am replacing ALL of the wiring with a Painless set, replace the ends with new ones where I can and see what breakers and relays I will need to add. I thought it was the bulk head connector, I cleaned it and checked it. At least today it shut down at my house.

 

[live4theking]

Man, I wish you were closer. It's gotta be a simple lose of contact somewhere.

 

[70 Droptop]

I had this happen on more than one of our 70 convertibles. Both times it was the main power wire under the steering column in the connector that went to the ignition switch. The top isnt powered through that circuit since it's powered at all times without the key on. On one car the terminal had gotten hot from the bad connection and was slowly melting the connector. I went through the bulk head connectors and other things til I finally found that as the cause. Put new terminals on and hasnt done it since.