'72 Brave electrical problems

[maty111]

Its a 1972 brave, in fairly good condition for its age. Its always ran pretty well. Its on a dodge chassis with a 318. Im still trying to figure out what year, the motor seems to be a '76? Im at a total loss what year the steering column is, but will get to that.

I was on the road, close to home. I was about to turn right so I turned my right turn signal on and everything died. everything, dead.
Thank God there was a small group of us in the winnie, we pushed it into the gas station parking lot. I discovered a 25amp in line fuse in a 8 gauge wire running from the hot side of the starter solenoid to under the dash. every time I turned the ignition on the fuse popped. Gave up, got my truck and trailer and hauled him home.

So im mechanically talented. you have to be to own a 50 year old rv
I replaced the whatever gauge wire from the battery to the starter solenoid. It looked rough.
I replaced the 8 gauge wire from the starter solenoid to the harness under the dash, with a new inline 25amp fuse
A new ignition switch and harness. from a dodge dart?
And a new turn signal/hazard/horn switch harness.

Now....
I can turn the ignition on, and have lights, turn signal, blah blah, but If i crank it a couple times the fuse pops!
[moderator edit]
I kinda fixed it???

Anybody have any suggestions? Electrical issues are not my favorite

Thank you
Matt

[Skip426]

Originally Posted by maty111

I replaced the whatever gauge wire from the battery to the starter solenoid. It looked rough.
I replaced the 8 gauge wire from the starter solenoid to the harness under the dash, with a new inline 25amp fuse

I'm thinking that the wire you replaced ;" looked rough" was actually a fuse wire , and that you have a major short still in the system .
Had the wire melted through the insulation in the middle of the section of wire?
Think of the fuse wire as the whole house circuit breaker , replacing it with a straight wire is asking for trouble.
Do you still have the wire ?
Can you post a picture of it?
I started working at Chrysler in 75 ; put in 30+ years;mostly electrical , but now that I've been retired for 10 they cut off my online access to wiring diagrams , so I'll have to rely on the net to check things out. You may have internal problems with the alternator , so disconnect the main cable from the alternator , isolate it and try starting again , stop if you blow another fuse . I'll be back.

[Skip426]

OK, I've got wiring diagrams , but the pdf files show a single page under the hood then a second page under the dash , so I have to print them to line things up.
The 25amp fuse has been installed in place of a fuse wire , and until I print out the pages I can't say if that fuse size is enough to replace the capacity of the fuse wire.
If the fuse only blows while cranking the engine , that will narrow , the areas for a possible short , down.
More tomorrow , after some head scratching.

[Skip426]

OK, more on what I've found with the wiring diagram/schematic I downloaded.
First I'd forgotten how bad the wiring, and manuals, were; back in the day.
The whole power for the entire coach is running though the 25 amp fuse that some one installed to replace the fusible link, ( fuse wire ).
But you already knew that , or at least you should have figured it out when the RV died on the road.
I've been unable to get an amp rating for the original equipment link, BUT at bare minimum it would have to match alternator output amps; and then some; , because the battery is charged through that link. Picture below.
I can understand how the fuse blew; it's easy to draw over 25 amps with the coach running . Brake lights,signals,radio , dash blower etc.
But back to the problem now, why won't it at least start , when you are only putting minimal load , on the system , when it did run with only a 25 amp supply before.
What the diagrams don't show is the firewall bulkhead connectors , and I thinking that with the problems the previous owner had to burn up the link in the first place you need to separate the connectors and check for damage from overheating , like the, " A " arrow in the second photo below. "B" is the fusible link going to the dash board, the overheated spot was probably the alternator output wire , as you can see someone has run wiring through the fire wall to by-pass the connector.
Just a few years after your chassis was built Dodge started installing harnesses with multiple fuse wires , to spread the load , then they started moving the fuse box closer to the battery and installing bayonet MAXI fuses instead of fuse wire.
I'll keep digging for an amp rating for the fusible link , and get back when I can provide more info.

[maty111]

skip,
thank you for your input

The wire that looked rough was a 4ga wire running from the battery to the starter solenoid
The fuse-able link definitely sounds correct. and same with the melted/damaged connectors. The hot wire running from the ignition switch was actually hardwired because it looks like it was damaged within the plug
buuuut......
I think i figured it out. It was getting a little dark this evening. I put a fuse in the inline fuse holder, it would pop. but at the same time i noticed a little flash coming from the intake manifold(the hood was off). My guess, it the hot lead for an electric choke was touching the intake manifold and grounding out.
Im a little grumpy that that was the problem, but also relieved that was the problem haha
but while were talking about it, it there someone/somewhere that sells the other wiring harness under the dash? I would like to correct the bad connectors

Thanks again
Matt

[Skip426]

The electric choke is shown as having power from two sources in these diagrams It shows a white/black tracer wire going back from the alternator power stud, that would be battery power, AND a red wire from a splice fed from the ignition switch.
But the red might just be an activation signal from the ignition to the choke heater timer and the feed from the alternator the main power. So the actual heat element may not be in the diagram , just the connections to the timer.
I'll have to track down one of the timers to double check .
Years ago I could have remembered all this stuff ... now I have to look it up .

EDIT : I'm still looking for an amp rating on the fuse wire , and I still have a length of the blue fuse wire in my tool box and there's nothing on it. Has to have been there 20+ years.

[Skip426]

Matt, I can't come up with amp rating for the fusible link , but because of it's location , and the fact that all charge from the alternator to the battery runs through that wire and the amp gauge on the dash , I'd think that any fuse in the wire should match alternator output. Depending on equipment that could be 45/50/or 60 amp.
But if the rest of the dash wiring is bad , I'd hold off on that .
The dash harness may be similar to a B series van , but the last time similar wiring was used would be 77/78 maybe 80. So 37 years old, and possibly in no better shape.