'65 Dart-Lights flickered, lost electrical, loud bang, car died

[goodjobgabe]

Above is the cliffnotes version of what just happened to my car! I've got a '65 Dart 270. I was cruising down the freeway and noticed that my lights--both my headlights and my gauge lights--were flickering, but only between being dim and being bright. Suddenly, my car lost all electrical power, I tried pumping the gas, heard a seriously loud bang that scared the hell outta me, and I pulled over.

No headlights or electrical at this point, but my battery reads 12v. I did see some smoke in my rear-view mirror when I heard the loud bang, but I have no idea what that was about.

My hypothesis is that my electrical system got shorted out, and I'm thinking that the boom I heard might have been a backfire. There was never a burning smell, nor leakages. My battery didn't blow up, and the rest of my engine looks normal and undamaged upon visual inspection.

At this point, I feel like I've got a riddle on my hands. Any help that could be offered is WAY appreciated.

Thanks y'all!

Gabe
Seattle, WA

 

[67Dart273]

If you lost all electrical power you have likely failed the master fuse link, which is the only protection the system has from some failures.

You can get wiring diagrams which are somewhat useful at MyMopar:

http://www.mymopar.com/index.php?pid=31

here:

http://www.mymopar.com/downloads/1965/65DartA.jpg

http://www.mymopar.com/downloads/1965/65DartB.jpg

and here's a 65 shop manual...................

http://www.forabodiesonly.com/mopar/showthread.php?p=1970088657

here

[ame="https://www.dropbox.com/s/upks33txhbe9tjw/1965%20Plymouth%20Service%20Manual.pdf"]https://www.dropbox.com/s/upks33txhbe9tjw/1965%20Plymouth%20Service%20Manual.pdf[/ame]

Wiring diagrams start page 8-96 Since this is Plymouth, you want model AV-1 or AV-2 for Valiant

Engine compt. wiring is clear down page 8-109

If you look at diagram "B" from MyMopar, find the starter relay, and from the top terminal, the left of the three wires you'll see is the fuse link which feeds through the bulkhead to the interior of the car.

First thing I'd do is unhook the alternator output wire at the stud, and tape off the wire. Then check and repair the fuse link. Unhook the battery ground while doing so.

Next, you want to find the short withOUT causing more damage. To do that, unhook your battery ground, and hook a test lamp in series. What this does, is any draw on the battery will show as a light, and nothing can "blow" as the lamp limits current. Make sure everything in the car is off, including the dome lamps, and see if you get a light at the test lamp.

By the way, a "big" lamp is better than smaller (wattage) for this purpose. A stop lamp or even a headlamp works well.

If the lamp does not light, touch your unhooked alternator output wire and see if it causes a light. If so, the alternator has internal problems

If the lamp lights, start by unhooking fuses one at a time in in the car.

Post back with results

 

[goodjobgabe]

Alright, I hate to sound like an idiot but this is next to gibberish for me! Mechanical stuff makes sense, but I know next to nothing about electric systems. I finally just got some time to go outside and try a few of the above suggestions, but I got confused. So, let's start small:

How exactly do I go about checking and repairing the fuse link? I need instructions to be this simple: Where do I connect the gator clip end of my testor light, and where do I touch the probe end?

Thanks for bearing with me, I really appreciate it.

 

[67Dart273]

I'm not sure I can make this much simpler. SOMETHING has caused the fuse link to fail, and it might be something serious enough to burn up a wiring harness. THAT is why you need to try and find the short, not just fix the fuse link

Do you recognize the starter relay? Should look something like this:

The main battery cable goes to that big stud at upper right in the photo, and the fuse link takes off from there and feeds power in through the firewall into the interior of the car.

Once again, I refer you to the diagram "B" I posted above:

http://www.mymopar.com/downloads/1965/65DartB.jpg

On that diagram, find the battery, trace the RED down to the left and find the STARTER RELAY

Then from the terminal on the relay, trace the wire coming up and to the left which is labeled

"FUSIBLE LINK (dark blue tracer)

That goes up to and through the firewall beside a large black wire, which is the alternator output

You will eventually need to go downtown and find a parts store who can sell you something in a fuse link.

But BEFORE you try and repair that you need to ATTEMPT to find the short. This is why you need wire a test lamp in series with the battery---because the test lamp will act as a current limiter and protect against more damage.

1---Disconnect the battery ground cable for safety


2---Find the break in the fuse link, (I'm sure there will be one) by tracing and feeling the wire with your fingers. Cut out the "bad" part and TEMPORARILY wire in a jumper even if you only use a "test" clip lead. This "repair" for now is only for TESTING

3--Now take your test lamp and fasten one end to the engine block or other place where it will be well grounded. Take the other end and solidly hook to the battery post. One good way to do this is to take the test lamp probe and clamp it to the battery post with some sort of C clamp, carpenter's clamp, Vise grip, or even just regular pliers with a great big rubber band. Use your head

4--I'll bet the lamp lights. Close the doors, make sure the trunk lamp is out if you have one, and that everything inside the car is off, lighter, radio (if wired hot) dome lights, etc, etc. Check around.

5--If you are sure that everything is off, move to the alternator. There will be one LARGER wire hooked to the alternator with a nut and stud. This is the output of the alternator. UNHOOK that wire, make sure it does not touch ground, and see if the test lamp goes out.

If the lamp goes out, you have a bad alternator and have found the problem

If the lamp does not go out look elsewhere

6--If the test lamp remained LIT in the step above, go in and pull fuses one by one, and look at the lamp for each. If one fuse drops out the lamp, either there was a load turned on at that time, or that is the circuit where the short was located.

7--If the tests above do NOT result in the lamp going out, post back and we'll move onward

 

[VDART]

your loud bang was most likely the built up fuel firing when the power momentarily was restored.

check your muffler-- to see if it is still good.


all other advice --see previous post -- very good info to find your problem ,Lawrence

 

[BillGrissom]

I don't know why everybody wants to make electrical trouble-shooting into some mystical thing that only gurus can approach. If you insist on that attitude, then take it to a maybe clue-less mechanic who will hack up your wiring and charge you big bucks. The wiring diagrams for these cars are very simple, compared with those for modern cars. You can even get cartoon versions with thick colored wires. To use one, just stick your finger on a wire of interest and follow it thru the diagram. They tell you not only the color, but the wire gage, so should be easy to locate any wire. If you think they teach this in engineering school, dream on. Fourier transforms yes, not basic wiring. Next step is to know how to use a multi-meter. I am sure youtube or wikipedia can inform.

 

[67Dart273]

I can understand, Bill. For men, the vertboten magic was automatic transmissions. Since I've now "got my feet wet" into a TF, I ain't so nervous, anymore, LOL

 

[TylerW]

Maybe an easy way to understand to understand the electrical path is this:

From the battery the 12V heads in through one or more fusible links to the bulkhead connector on the firewall. On the inside, there's the other half of the bulkhead connector.

Then, the power goes to the ammeter, then the fusebox. After that, you have circuits that go to the lights, without going through the ignition switch, and some that go through the ignition switch to only operate items when the key is on, like ignition, wipers, fan motor, turn signals, reverse lights, radio.

The fusible link is simply a piece of wire that acts like a fuse. When something increases the amperage load too much downstream of the link, it melts and parts the circuit. That just saves the wiring inside the car from going up like a torch.

A very quick test to see whether there is a short inside the car is to take a digital multimeter and select the ohms position. Ohms measures resistance but using the meter it is also an easy way to check whether you have a path to ground when you shouldn't have.

Turn the meter on. Notice when you touch the two leads, the meters goes to 1. or thereabouts. Take one lead and ground it. Take the other lead and probe the circuit that feeds 12v into the car. If the fusible link parted then you will have to get past the link toward the firewall to make this test valid.

Just think of it as completing a big circle. You're starting with ground on the one side of the meter and you are investigating whether you can complete that ground circuit with the other side of the meter because the positive side of the electrical system has shorted to ground somehow.

Think of it this way to make sense of what you are doing: If you take the probes and touch them, the reading goes infinity. You are going to ground one probe and use the wiring circuits to see whether you can complete that same effect, which will happen if one of the wires or switches in the POSITIVE side(which should not ever be connected to the ground side no way no how) is doing something where it is IN CONTACT with the car metal or a positive 12v wire somehow.

If you probe the wire and get no response from the meter then there's not currently a short to ground on the circuit that is past the fusible.

If you get that same "1" reading as when you touched the probes then you definitely have a wire or switch that has grounded somewhere.

You can do that same simple test all the way up those circuits into the car and through the fuse box until you find the particular circuit that has the ground condition in it. Then you can isolate it and make the repair.

One way to do it is start pulling fuses 1 at a time until your meter stops responding. When you pull a fuse and the meter stops responding, there's your affected circuit.

All the help so far has been very useful, maybe this will provide a less intimidating way to approach it.

You need a meter though for sure and don't replace the fusible links with plain wire, you'll burn the car down. You can buy fusible link wire at most parts stores.

Whew.