1973 Dart No electrical power

[SputnikOne]

Hey all, me again.

As part of my process of bringing my 73 Swinger back to life I Installed a Retro sound radio and speakers into the vehicle two nights ago.

For reference, I used the red cigarette lighter wire for the constant battery voltage, and added a wire off of thr black wire from the turn signal flasher for switch power, and grounded it to a big metal screw in the dashboard.

The night I installed the radio everything was working fine the radio came on and everything worked.

I left the car for about 24 hours and came back to it this morning and absolutely nothing has any electrical power.

The battery has just over 12 volts, so I don't believe that's the issue.

But nothing seems to be getting and power, the key buzzer, door light, gauge lights, and everything else does not react when I insert and turn the key, and obviously the vehicle does not start either.

I've started to troubleshoot on my own, I took off th connector just before the fusible link by the bulkhead and used a multimeter to test voltage from the battery side of the connector to a ground and got a very inconsistent low voltage at about 4-6 volts every now and then.

On top of that some of the fuses show the same 4-6 volts on their terminals when I know they showed 12 when I was installing the radio.

Any ideas? Could it be the starter solenoid or relay?

 

[MadScientistMat]

Check the fusable link itself. Does it have a voltage drop from one end to the other?

 

[SputnikOne]

Well like I said I checked from the battery to just *before* the fuseable link and couldn't get a decent voltage, I'll check that too but I believe the problem might be further up the line.

 

[67Dart273]

Chase the obvious. Check battery voltage RIGHT ON TOP of the battery post, then move to the clamp, then move to the big stud on the starter relay.

Next find the "big red" going from the fuse link at the starter relay, into the bulkhead connector. Probe that bulkhead connector terminal ad see if you have power there.
If you do, then check at the alternator. If no power, the problem is either a bad terminal in the bulkhead connector, bad connections at the ammeter, or (rare) possible the "welded splice" which is in the black ammeter wire a few inches from the ammeter. It is wrapped up in the harness.

DO YOU HAVE a service manual / wiring diagram? They can be downloaded, free, from MyMopar.com

Some of them there, as well as the 73, got there because of some of us right here

 

[SputnikOne]

Confirmed, there's no continuity through the fusible link, got better voltage on the battery side with a better voltmeter, but the bulkhead side is dead.

Now I wonder why.

I don't think the radio would've overloaded the power system like that, it's just a 12 volt system and it's power wire has its own fuse on it that's like 10 amps.

My theory is The battery drained abit when I was installing the radio as the door was open so the headlamp was on for an hour or two. Eventually the radio started to show signs of low power, cycling on and off constantly, so I, probably mistakenly, started the car (that has a new style roundback alternator currently installed) and probably over amped the link (assuming the alternator current goes through the link.)

Should I just replace it and be careful to not do it again? And what should I replace it with? There isn't like a amp rating or anything on the link.

 

[MadScientistMat]

Best bet is to use fusable link wire (available at NAPA) in the same gauge and length.

 

[SputnikOne]

I agree but all the ends ( I need the little circular connector type on one end and the pin for bulkhead connector on the other end type) and no one seems to have that.

 

[SputnikOne]

Well, I went to depin the fusible link wire from the bulkhead connector so I could remove It, and it's alittle hard to see down in there, but it's *very* stubborn, I loosened the hook pretty much all the way and the pin doesn't move at all, I attempted to give it a good tug and the pin pretty much just broke, and nevertheless still won't budge. The wire it's connected to is pretty loose and I'm worried it'll also just break off and the pin will just be trapped with no way to grab at it.

 

[67Dart273]

Think how old these girls are. Fuse links can maybe been pre-overheated and partially damaged in a previous event, or corroded. In fact I had a main battery cable on a Ranger corrode internally. The ground went from the battery down to a factory "T" terminal that bolted to the frame, then continued on to ground to the block. One day the Ranger would not crank, yet the headlights worked. Right after that "T" tap terminal, the cable was powder.

One way you can troubleshoot for shorts and guarantee you don't burn stuff up is to find an old heavy lamp, like a headlamp, or 1 or 2 stop/ tail lamps in parallel for more wattage. Put the device in series with the battery ground, and if the short appears, all it will do is light the lamp.

 

[SputnikOne]

I'm *pretty sure* the link blow was probably caused by the alternator charging the battery I admittedly let the alternator charge from way too low, but I didn't notice any abnormalities while it was running, just shut it off after testing the new radio and left the car for about 24 hours as I was on Duty, so I don't really know when exactly it happened.

 

[townsend]

Just for reference, is this the fusible link that you need.

Pardon Our Interruption...

The plastic connector in your picture is available new if needed.

 

[SputnikOne]

Looks like the one, yes.

 

[67Dart273]

I'm *pretty sure* the link blow was probably caused by the alternator charging the battery I admittedly let the alternator charge from way too low, but I didn't notice any abnormalities while it was running, just shut it off after testing the new radio and left the car for about 24 hours as I was on Duty, so I don't really know when exactly it happened.

Do you know what is the alternator rated output? Yo do NOT want much over a 50A on stock wiring.

Also, bad connections such as degraded terminals in the bulkhead connector can heat the adjacent wiring, causing stuff like breakers and fuses to become de-rated, AKA trip, blow early

 

[SputnikOne]

Here's the back of the spade, or well, what's left of it.

I have no idea how if at all I'm going to get this free.

On a related note, does anyone sell replacement '73 dart 225 slant six engine bag wiring harnesses? I can't find any for this specific arrangement.

 

[townsend]

You could transfer all the other terminals to a new plastic connector and then cut or chip away the plastic around the bad terminal.
Maybe a heat gun would soften the plastic.
New connector can be purchased here:

NOS MoPar Bulkhead Connector 66-76 Barracuda Dart Sport Duster Valiant Demon | eBay

This connector has the center locating tab. Plymouth Valiant, Barracuda (1966-1969), Duster. Dodge Dart, Dart Sport, Demon. Mopar # 2631318.

www.ebay.com

 

[67Dart273]

You need to REPLACE ALL those terminal pins, and likely the ones in the mating half of the connector as well. That big wire may be heat damaged enough you may need to cut it back and splice in a new length, or unwrap the harness and replace it. I would guess that one goes to the alternator output.

If you cannot salvage the connector shell, you can either drill through for the damaged ammeter circuit and run new wire straight through, or find a connector shell. Put a want ad here in parts. There may be an outfit that repops them

The terminals are available. Mattax has a great thread on the different types of these connectors, "Packard" We used to call them "Packard 56" but that is not quite right, for all of them

 

[SputnikOne]

Decided to just take the nuclear option and bite the bullet, so I'm just going to replace the engine bag wiring harness and get rid of this rats nest of electrical disasters.

I'll have to rewire my custom lights again, but at least now I can do it better knowing what I know now.

 

[SputnikOne]

Hey again, so I got the replacement engine harness, tore the old one out and replaced it.

Got everything wired back up (Pretty darn sure it's all where this supposed to go), went to cold start it and it made this rather awful sound and rumbled *alot*, I shut it off as quite frankly it scared the **** out of me, it usually cold starts just fine and the rumble and whatever that squeak is is definitely new.

 

[SputnikOne]

Some photos of the new harness, haven't finalized securing everything down just yet.

 

[SputnikOne]

The only new thing this harness has over the old one is the electric choke assist is powered now.

 

[SputnikOne]

Hey, sorry for the bump.

Replaced the harness and everything worked fine for a week or two and today seems like the same symptoms just appeared, car started and drive perfectly fine to an appointment, then I brought it back and parked for like 30 minutes, and now there's just zero electrical power in the vehicle again.

It could be the fusible link again, but it wouldn't make sense for it to be fine until I turn the car off, it should stop running if it blows right?

 

[SputnikOne]

Also of note, humored myself and tried it again, the door buzzer worked when I put the key in but the oil pressure light didn't come in so I knew it still wasn't getting power, once I removed the key the door buzzer won't sound anymore if I try it again.

 

[67Dart273]

I don't remember if the 73 has more than one fuse link, do you have a factory manual/ wiring diagram? On the older ones, for sure, the main fuse link blows, NOTHING will work, nothing from the key, no dome, brake, or headlights.

EDIT took a look at the 73 manual. Looking at the diagrams of the engine bay connectors, "CE-5" is the starter relay. That only shows one fuse link

A1A-10R is the feed to the relay stud, coming off the battery
A1B-10R is the fuse link if not a 60A alternator, either it or A1E is not used depending on alternator

S5 of course goes down to the solenoid, and the bottom push on connectors are for the start circuit, neutral start switch, etc

How much all have you checked in the bulkhead connector, terminals condition? Ammeter connnections, terminals and ammeter itself?

 

[SputnikOne]

I can take a took, but I swear the only one I saw was the bulkheadconnector relay, but worth a shot I suppose.

That could be the same fusible link just the rest of the wire isn't portrayed.

 

[SputnikOne]

Well, I just checked it again after letting it rest for 6 or so hours and everything works again, don't know whether to be glad or confused, but I'll let you know if anything changes I suppose.