I am helping a friend with a car that he just picked up. A 70 V-code, 4 speed, Road Runner which is probably best described as a one repaint survivor.

Doesn't run well, barely starts, wiring has been hacked in to multiple times...every harness, and I mean every.

To get started, we decided to replace the engine harness which had a clumsy modification to add a Mopar ECU, several areas of burnt insulation and was in very poor condition. I've modified new Mopar engine harnesses to add Mopar Electronic ignition many times, I am sure that I got it right and with solid connections (I checked multiple times as we ran into issues). While doing this, I noticed multiple hacks and splices to the headlight harness and the very poor way the neutral safety switch harness had been repaired at some time (at least 4 splices). So I cleaned up the connections, replaced two almost broken wire connections to the bulkhead plug, but left how it was done alone figuring I would come back to it.

We go to start the car and we end up with the situation where we turn the key and nothing happens. But here is the really odd kicker...we noticed that when the key is in run or start...THE CLOCK STOPS! The clock runs otherwise with the key off and in accessory mode. Also...no headlights or dome light at all.

As I said the headlight harness is original, and hacked. Since the car was brought to my friends garage he told me that he had a moment with it where it wouldn't turn over and he moved some harnesses around under the dash and it worked again!

I checked, the connectors to the column are tight and look fine. There are no burn marks or melted areas on the bulkhead connector. I did notice by putting a lighted borescope under the dash that it looks like the black wire to the altimeter gage has been repaired at some time, the red is fine. There are no signs of damage to the gage +/- posts.

So what could happen circuit-wise that putting the key in to run and start is so bad that the clock stops! Prior to messing with the harnesses the car did turn over but started only very inconsistently, battery is charged. What started as a 6-pack tuning exercise has turned in to a "turn the key and stand next to the fire extinguisher!"

THOUGHTS?????

get a wiring diagram for this car, and trace all the starter switch wires from the key to the engine's starter components.
look closely for burnt, broken, or hacked wires and splices, and go from there.
as i'm not seeing what you see, it sounds like a complete replacement harness for the whole vehicle would be a good idea.
lacking that, you will have to trace each item's circuit from under the dash to under the hood to really see what kind of hackery has been done.
i believe you will learn a LOT about wiring with this car.

Wow, something is really messed up. Typically the clock is fed from a power supply 'hub' that feeds multiple devices that are energized all the time. The fact that the clock is now tied to an ignition feed is a major problem. If it was just one thing I'd say troubleshoot and repair. But with the amount of work a "Tommy Tinker" has done previously, I'm with moparx that a complete new harness is in your future.

I would buy new replacement harnesses for the engine, front lights and under the dash and swap them out now

Bad ignition key switch ????

Mike

Cab is correct..
If the original wiring and harness has been hacked up, time for a new wiring system.
Many times a car guy will come to me about an electrical problem, but I take a look and find multiple splices, crimp connectors, wire nuts, loose unconnected wire stubs so the only fix is a new wiring harness.

Just my $0.02...

From what you describe I believe that you had an under dash ammeter wire melt. These types of meltdowns are common and cause many really random problems.

If you are reasonably proficient at wiring you can repair it yourself. I used to do them all the time which is why I am now reasonably proficient. LOL

Start by checking the basics and get a wiring diagram.

Basics,

1. Are the bulkhead connectors fully plugged in and are the terminals fully seated on each side of the bulkhead. Not uncommon for the harness to have damaged terminals or the place the terminals seats is damaged and the wires move out of place when you push the connector on.
2. Voltage correct to the ignition switch and if you disconnect the switch does the voltage paths/wiring respond correctly? ie does it have open continuity to the start circuit until you rotate the switch to start. etc.
3. Is the dash properly grounded? A bad or intermittent ground will cause all kinds of problems such as the clock starting and stopping.
4. Ground the wire to the starter relay from the neutral/park switch and see if the car cranks with the key. A no crank after you messed with the neutral safety switch wiring could be a sign that a repair didn't take.

Be vigilant on the wiring harness. I have seem more than one bad diagram floating around on the internet. Typically it will say that the XYZ wire is supposed to be in position 12 and it is actually position 11 OR it will be in position 12 on the engine diagram and 11 on the dash diagram. I have also seen people move the wires from a bad connector spot to an empty one messing with the OEM pattern. My 74 RR had the wire moved by the previous owner on the engine side of he connector and when the ECU didn't fire put in a points distributor as a fix.

After the basics are covered if you choose to repair the harness this is how I do it.

1. Remove the harness lay it on a table to unwrap it. It isn't just one linear harness it has branches and random wires exiting the main harness so I use plastic ties or tape to keep the bundles grouped and random wires marked.

2. After unwrapping I check the big wires for meltdowns and look closely at any wires in the harness near the meltdown. When they melt they rarely take out 1 wire. Repair as necessary.

3. I then run my fingers down each wire feeling for weird spots. Squeeze it between 2 fingers and slide along the wire. Repair as necessary. This is important because it is real easy for damage to hide from your sight but harder to hide from your feel.

4. I upgrade the red and black wires to a larger size and leave plenty of excess hanging loose. I then run those wires through a hole in the firewall and use a much beefier connector, a bulkhead pass through or solder the wires on one side. I do this to bypass the OEM bulkhead connector. They are a weak link.

5. CHECK THE AMMETER INSULATORS a commpn problem that causes shorts and burned wires.

6. Make sure the engine side has a fusible link. DAMHIK....

If you decide to repair the harness NAPA or Amazon have lots of wire colors if needed and the packard terminals.


Or like others said buy prefab harnesses. They are easy, but not cheap.

Hope it helps.

X3