Quote: That was a fabulous link.
H'mmm. I'm not sure how the amperage rating of a fabulous link is determined. It's hard enough determining the rating of a fusible link!
Quote: Now, I still would like your recommendation for what size fuse to replace this link with. It seems as if it is the wire size of othewise unprotected wires under the dash that need to be taken into consideration. This entire design seems a little suspect to me.
Well, the original idea behind the fusible link was "cost effective" circuit protection, which is a diplomatic way of saying cheap! Replacing a fuselink with a fuse is really kind of a moving target/best-educated-calculated-guess kind of situation. If you can try to closely calculate the maximum operating load of the circuit to be protected, and add a reasonable safety margin (not too large, not too small) you'll get close.
Quote: On my '70 Dart, the yo-yo who had the car before me replaced the fusible link with plain wire. At some point he had run a screw through the steering column and shorted out the big red wire for the flasher circuit. His solutiion was to remove the flasher.
Sounds like a regular Silas Barnstable type! Did you find any of the fuses wrapped with tinfoil from chewing gum?
Quote: subsequently put a flasher in it, and tried the circuit, EL FLAMBEAU! But, it was the wiring harness under the dash that went up in flames. You never saw an old man move so fast in getting the battery unhooked,while smashing at burning wires with his bare hands.
I can relate. I thought I must've told the story of when my father and I replaced the horn in his (now my) Lancer, but extensive searching fails to turn it up.
Dad wasn't into cars and didn't know much about how they worked, but we worked on the Lancer as a father-son type of thing. By and by, one of the car's two horns stopped working, so I grabbed one (sourced from a wrecking yard) off the garage shelf, tested it on the workbench with a reasonably well charged 12v battery, got some noise out of it, figured it was good, and dad and I proceeded to do the simple swap.
Once the "new" horn was in place and hooked up, dad put the battery cable back on the battery. I leaned in the passenger door and touched the horn ring. The new horn began to emit a squailng sound (kind of a mix of squawk, quack, and wail) which didn't stop when I jerked my hand away from the horn ring. After what could not have been more than one second, there was a giant puff of smoke, a loud frying sound, and the horn stopped making noise. All of this right in front of my completely stunned father and me. I scooted fast round to the battery and yanked the cable off, but I might as well have taken my time and stopped for a coffee on the way. The entire engine wiring harness was charcoal, burned beyond recognition — And it hadn't taken more than 2 or three seconds, though those two seconds went by in super slo-mo.
We stared at the smoke still curling up from the ruined wiring, and stared at each other, and stared back at the wiring, and back at each other. Obviously, the horn wasn't as good as I'd assumed based on my quickie bench test. I started apologising, but he waved it away and said "Dan, I think if you'd done something damn-fool, we'd both know it." It was just one of those things.
Of course, that still left us with a garage monument (non-running, non-driving car — and it was dad's only!) until it could be fixed. I was in high school at the time, so the next day on my lunch period I drove my '65 down to Santa Fe Blvd where there was a little-known wrecking yard, set back from the road and sunk down to a level well below it. I knew there was a '62 Valiant there (it contained one of four or five aluminum 225s around the Denver area that I kept meaning to go get and never did...). The yard was fully staffed with scary dogs and even scarier goons. I asked about the '62 Valiant and one of the goons chewed on his wodge of tobacco and said "I donno, twenny bucks for however much wiring you want out of it." Mmkay. Working quickly but carefully, I removed the engine wiring harness and a goodly portion of the dash harness, paid my $20, and gave the dogs wide berth on my way back to my Valiant.
On the way home from school that day, I stopped at a coin-op car wash, hung the engine harness on the wall by the floor mat clips, and powerwashed the grime off. It was in basically perfect condition...score!
That night, dad and I put in the "new" harness. It didn't take but about half an hour, working carefully; there aren't many wires on a '62 compared to later cars, but they're all important. The only wire we didn't connect was the one to the now-absent low-note horn.
That harness is still in the Lancer, but now it contains some main circuit protection (I don't recall what type or rating).
OK, enough reminiscing. You write:
Quote: This wire into the bulkhead connector carries power for most everything but the starter motor itself. It feeds the ammeter directly and everything goes on from there. The enigma here is that it seems like this should be a much bigger fuse than anything indicated in Mini Mopar's chart, but on the other hand it must protect a few more delicate, unfused circuits inside the dash. So too big doesn;t protect some circuits, and too small won;t handle the total power needed. What would be a better way to wire this?
Add individual protection for the small presently (almost said "currently") unfused circuits. The main circuit protection is a last-ditch safety device designed not to protect the branch circuits under it, but to prevent the car burning to the ground in the event of a major electrical catastrophe.
The main circuit protection therefore is properly selected as described above: Total up the maximum possible current through the circuit to be protected, making sure to include transient but normal conditions (such as extra current draw from the wiper motor when it's struggling against snow and ice), add a reasonable safety margin, and go from there. It's best to "split up" the safety margin. That is, don't just tack on more amps, but rather select a narrower safety margin and use a slow-blow circuit protection device (such as a fuselink or time-delay fuse or slow-acting circuit breaker). This way you allow safe transients without popping the protective device, but if there's a big, serious overload, the device will open the circuit.
Quote: I have decided to redo, pretty much in it's entirety, the wiring of this car.
Probably not a bad idea. Steer clear of the sadly-empty promises from the likes of "Painless" wiring.
Quote: It is very hodge podge
A hodge podge Dodge bodge lodged in your garage?
Cole-Hersee are very reputable, as are Cutler-Hammer and Buss/Bussman and Littelfuse and various other makers of circuit protection and build devices. I just had a customer the other day point me at this nice-looking fuse block. Hella and Bosch also make very good relay blocks and boxes, fuse blocks and boxes, junction blocks and so forth.
Quote: I intend to draw a diagram of this new plan first, not only to check the logic of it, but to have something to refer to in the future, which I have never had before.
Very good idea.
Quote: Thanks a bunch guys. I know this question blew all out of proportion to its original intent, but that's how my hobby projects seem to always go.
Always!
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