Thread: fusible link question

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Double post, operator error.

Yes, talking about the main feed to fuseblock from starter relay.

Haven't made the fuseblock mods yet, but I did inspect the terminals, and they look ok. Amps guage too. I'm still excited about making the changes, but really want to find the real problem first.

So far, all I have found for sure, is the main circuit has to be good for MORE than 30A, and the wiper motor pulls 2A MORE on low.

Right now, this is my thought:

Probably every bulb in the car pulls more power than the original, so that the lighting circuit is probably 10% or more over factory specs. Thus, the fusible link has been at capacity for a long time. Thermal cycling probably has reduced the full load capacity of the fusible link, so it was doomed to fail. Also, just judging from the guage of the link, I'm guessing it was undersized from factory. Considering this car is AC, power Windows, rear defrost blower, it seems the fusible link was doomed to fail, simply undersized.

I'd say you need a Maxi Fuse in the 75 to 100 amp range.

I'm starting to lean in the direction of a stranded ten guage wire.

A fuse / fusible link in front of the fuseblock. What is really the point?

Is there really a significant chance the 18" of wire between it and the battery is going to short out?

To me, the "point" is not so much the short piece of wire leading to the fuse block, but is the primary side of the fuse block itself, where that power splits into the fifteen to twenty feeds into the fuses.

And I would eliminate the ammeter as well per post #4

Originally Posted by firebird77clone

Is there really a significant chance the 18" of wire between it and the battery is going to short out?

You're thinking only of a wire failure, often it is the insulation failure that causes the short. When the insulation fails, it is the current protection (fuse, breaker, fusible link, exc..) that prevents the fire. Crosslinked insulation is used in automotive wiring due to the increased heat demands on the wire's insulation.

I'd started to say that I've never put a fuse in front of a fuseblock, but I guess I have.

Every cabinet I built has a master breaker in the door, feeding a fuseblock.

Every breaker panel or even fusebox residential I've installed has a master fuse or breaker

So from that perspective it makes sense.

But I'm still leaning towards a piece of ten awg stranded.

I patched in a length of 10 AWG stranded. Used a watertight butt splice at bottom, and a good ring terminal at top. From here out, the fuses are on their own.

Today I pulled the dash to fix the defrost, so it seemed an opportune time to inspect the fuse box. With everything out of the way, I was able to identify that it does indeed need the Mopar fuse box repair, so I'll be doing that tomorrow.

OK, I got the fuse block repaired. The hot wire I pulled through straight to the horn relay, eliminating my previous splice, with the watertight butt splice. The ground wire I just used some 10awg quick connects. The lock tabs broke off the connector plugs, so I'll have to keep an eye on them. I may just smear the plug body flanges with silicone to glue them in. I also bolted the ammeter ring terminals together, and wrapped with black tape. Thus the alternator gauge is out of business.

If you used regular old black electricians tape to cover the ammeter lugs take a small wire tie and put it over the tape end. That will insure that the tape can't unravel.

Originally Posted by NTFDAY

If you used regular old black electricians tape to cover the ammeter lugs take a small wire tie and put it over the tape end. That will insure that the tape can't unravel.

With black electrical tape, if you tug the tape to break it and "finish" the connection, it will in time unravel. The memory in the plastic will pull the end back.

To do the job right, cut the tape with a razor ( or scissors ) to finish or end the connection.

Originally Posted by 34_40

With black electrical tape, if you tug the tape to break it and "finish" the connection, it will in time unravel. The memory in the plastic will pull the end back.

To do the job right, cut the tape with a razor ( or scissors ) to finish or end the connection.

Over time with the drastic changes in temperature black electricians tape will unravel no matter what it's cut with. A plastic wire tie will insure that that will not happen. In the last 40 or 50 years I've never had one unravel and I sure wouldn't want a 12 gauge wire to become exposed under the dash. Doing the job right is not nearly important as how safe it is.

Originally Posted by firebird77clone

I also bolted the ammeter ring terminals together, and wrapped with black tape. Thus the alternator gauge is out of business.

You could use one of the amp meter's lugs as a junction point with no worry of the wire shorting against anything.