1970 300 - Replace Wiring

[Waggy]

I thought purchasing a new modern Painless Mopar harness was going to be the answer to my electrical problems and maybe one day it will! I have found Painless of NO help and I use to think I understood car wiring. I thought I had all of the turning signals working, but then I ran into some issues like when are the side marker lights, the running lights, and the other lights on? I found today, the turning right signals do not work now, the left dash left turning signal does not work, when I turn the headlights on and the turning signal, the dash lights flash and for some reason on the left side the side marker light use to flash (when the flasher use to work) but that did not happen on the left side.
Sure would like to see how the lights are wired. I have the manual but I find it hard to piece all the pages together and could not follow the lamp labelling for the lights. Any help would be appreciated.

 

[MYSINBIN]

I found the '67 version of this to be invaluable when I rebuilt the dash wiring in the Silver Custom:

1970 Chrysler Color Wiring Diagram

Spend the $30 for the large one sided version. (the smaller one is two sided which gets confusing when tracing a wire from one side to the other)

Between the FSM and the color wiring diagram, there is very little grey area left.

My approach is to return to factory specs. and then upgrade from there.

FWIW, I was able to find all of the necessary parts/supplies to repair/restore the original dash harness. (correct color wire, connectors, terminals, crimpers, wrap tape, etc.)

I also had access to a bin of spare wiring harnesses to pick from.

My initial speculation would be grounding issues and/or cobbled previous repairs that you haven't discovered yet.

Compromised grounding will have you scratching your head forever until you eliminate it from the equation. It could be as little as a bit of rust/corrosion on a light socket.

Hope the input helps.

John

 

[CBODY67]

Unless Painless Wiring has a harness specifically for your car, then you get the "universal" kit and are on your on. There are other wiring harness suppliers that have been around for a good while. From the early days in the street rod industry, one of Painless's strong points was to use OEM Packard electric/GM wiring specs and terminals, as the quality of wire in other vendors could vary in many areas, but look correct.

From the issues you've had, it might have been better to get all of the correct color code wires, put the correct terminals on them, measure, and continue from there. Which is pretty much what you've done, using the universal Painless harness to build from.

One other issue is to understand that few automotive circuits are really "two wire" circuits, unless the bulb holder goes into a plastic housing so it can't self-ground at that point, or a more reliable ground might be done with two-wire circuits and a common ground wire.

So . . . these projects can take more time than suspected, like some other car project items.

CBODY67

 

[Waggy]

The Painless harness (10127) I purchased was for 1966-76 Mopars, so it should have worked, I would think. The manual I am using is for a 300/Imperial and Painless said it worked for the Imperial but did not mention 300. I wish Painless had a diagram for their wiring harness.

I will check the grounds and go through all the wires. I have spent the last 3 to 5 years trying to solve my wiring problems. I have had it into shops and just got bills and no cures, so I finally said "Let's go with a new system". I checked new or reconditioned harnesses, but they seem to be a little different than what I had. I did not want to order the wrong one and I could not find an exact match to what the manual said, so I have gone this route! Some day it will be working or sold!

 

[CBODY67]

I hate that you've had all of these problems! And spent that much money with no real benefits.

CBODY67