Fusible link guage?

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Ghostsoldier

Ghostsoldier

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My fusible link in my '74 Duster fried yesterday, all the way up to the bulkhead harness plug. Since this left me with no excess to wire to connect into, I'm going to bypass the connector and install a fusible link in-line.

My question is this: What gauge do I need, 14 or 16 amp? I can't find it in my manual anywhere, and the wire from the battery looks like 10 gauge.

The stock dash amp gauge was pegging 40+ thsi week, so I think that's the problem...I'm going to bypass it when I re-wire the link.

Thanks,
Rob
 
First, go to local alternator shop, get charging fixed; field grounded, or bad regulator. Start engine, after 2 minutes, lay on your back, stick hand up, and grab the ammeter; try not to cut your arm/hand while yanking it off that hot sucker. Bypass it.

The alt guy should have fusible links; it's just not a smaller gauge wire. It's special.
 
Well, I went down and bought some 14ga. fusible link wire and some butt connectors, and hooked it back up, bypassing the block connection.

I also disconnected the amp gauge and bolted and taped the two wires together to bypass it; the connections were a bit loose on the gauge, anyway.

Now, I have limited power to the cabin, i.e., the aftermarket gauges, radio, etc., all work. What I DON"T have is any power to the ignition switch, fuel pump, horn, etc.

Strange thing also: the headlights work on high-beam, but not low-beam, and the turn signals/parking lights work on either setting. I checked the headlight switch while I was in the dash, and it looked OK; it had been working previously, before all this happened yesterday.

Could the ballast resistor cause this? I haven't checked it yet....

Rob
 
Sounds like you have some more electrical issues/burned up wiring somewhere in the car. With the two ammeter wires bolted together, you would have power to everything, just like if the gauge was still hooked up.

I've started and moved A-Bodies and 70's Dodge trucks around without instrument clusters and such, just by bolting the 2 ammeter wires together to complete the connection.
 
74Dusted said:
Sounds like you have some more electrical issues/burned up wiring somewhere in the car.
Click to expand...

I'll check the wiring again tomorrow....it's 25 degrees here tonight, and I'm inside where it's warm! :)

Rob
 
74Dusted said:
Sounds like you have some more electrical issues/burned up wiring somewhere in the car. With the two ammeter wires bolted together, you would have power to everything, just like if the gauge was still hooked up.

I've started and moved A-Bodies and 70's Dodge trucks around without instrument clusters and such, just by bolting the 2 ammeter wires together to complete the connection.
Click to expand...


I agree, if you had that much fusible link burn up, there is something else wrong, fusible link don't just burn up for no reason, it had to be over loaded or something shorted out.

Also, if you have additional accessories like aftermarket gauges, fans, fuel pumps, etc. you need to run an auxiliary fuse block powered from the battery, or a direct power supply from the battery. These accessories will overload the original wiring and cause problems like this.
 
One thing you can do to troubleshoot those kinds of problems without causing more smoke is to put a BIG test lamp in series with the battery ground.

It depends on the problem I'm trying to find.

If I have a low current battery drain, I want a small test lamp, so the normal commercial probe n lamp is fine

Certain other problems, I have a scrap tail/ stop socket, and so I can wire EITHER the stop or tail filament in, OR twist the wires on the socket together and wire BOTH stop and tail filaments into the circuit. The tail draws the least, the stop more, and the two of course together draw the most.

But for something you MAY have, that is, a massive short that blew up the link, I'd use something REALLY big, like a headlight bulb

First thing I'd check is the ALTERNATOR. If you blew up a diode, or somehow the charge wire got twisted over against ground, or if the insulator for the output stud broke, SHORT
 
Yes, if alt field shorted, it can take out all kinds of wiring under the dash. And if the ammeter wires were loose (usually are), that causes problems. sometimes no charge, sometimes calls for reg to over-charge.

I've been under the dash of a car that was putting out 18 volts. It took a while to trace and replace all the burnt stuff.
 
Well, I feel like an *** now...it turns out, in my haste to get it fixed last night (and get out of the mid-20's weather, as I'm a true shade tree mechanic, with no garage space), I inadvertently forgot to plug the center firewall connector back into the block--I had pulled it to find the burnt link--and once I did that, it started, and runs fine (so far).:banghead:

I let it run for about 15 minutes, and checked for smells, sparks, or any signs of deterioration, but couldn't find any. I also checked my alternator with a multimeter, and it seems to be fine. All the light work now, too.

I'm thinking more and more it was the amp gauge, because I've read here on FABO that it's a fire waiting to happen anyway, and with the 'pegging action', it definitely was having issues.

Since I drive the car to work every day, I'll be keeping a wary eye on it, just to be sure it's not something else that was causing the problem.

Thanks for all the help, guys. :)

Rob
 
I think the ammeters on ours cars are getting a bad rap. Most of the time, it's not the actual meter that is the problem. They're a real simple gauge and very trouble free. Most of the problems are in the connections on the back. They can become loose and the wires can then swing around and/or the posts can short out against the housing. Adding high powered sound systems can throw everything over the edge too but you can't blame the ammeter for that even if it's the first thing to fail.
 
I tend to agree with Cudamark. I have never had a bad ammeter on any of my cars. I'd look elsewhere. If your wires were loose you wouldn't pull more current, you'd pull less and that does not explain why you burned up the fuse link. You had to be pulling a ton of current for it to blow which means something is shorting to ground. You may want to reach up under the dash and wiggle things around to see if you can recreate the problem before you drive it down the road. Put an ammeter in series with your battery and have someone monitor it while you do this or you can just use the ole lightbulb trick as described above.
 
I'm 61, Mopars my whole life, since before I had a license. The terminals heat and cool , a lot, they loosen. Then anything can happen. No charge, no start, lights weird. Loose starts calling for more alt voltage, wires and connections get hot, etc.

Several times, traced down to loose amm wires. My 70 is bypassed, and who ever gets it, won't have to track down this old fix. Voltmeter!
 
Ghostsoldier said:
Well, I went down and bought some 14ga. fusible link wire and some butt connectors, and hooked it back up, bypassing the block connection.

I also disconnected the amp gauge and bolted and taped the two wires together to bypass it; the connections were a bit loose on the gauge, anyway.

Now, I have limited power to the cabin, i.e., the aftermarket gauges, radio, etc., all work. What I DON"T have is any power to the ignition switch, fuel pump, horn, etc.

Strange thing also: the headlights work on high-beam, but not low-beam, and the turn signals/parking lights work on either setting. I checked the headlight switch while I was in the dash, and it looked OK; it had been working previously, before all this happened yesterday.

Could the ballast resistor cause this? I haven't checked it yet....

Rob
Click to expand...

There are 2, a 16 and a 14.
 
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