Alternator Fuse/related harness or something worse?

[earlingy]

I had been having charging/low voltage issues. They were slowly getting worse, so I was checking fuses, and saw a wire in there for the alternator fuse that was kinda melted. I'd never seen or heard of a fusible link, so I thought it was just rigged in there... The folks at advance auto explained to me what it was, but since they didn't have a similar link and I didn't want to just put a random wire in there, I ended up installing one of those little fuse insert wires. Since wire around that gauge has like 17-22 amp flow, I started with a 20amp fuse. It instantly blew that, so I moved to 30amp. That held fine, but the charge issue was still there. I replaced the alternator and that fixed it.
Today, a couple months later, it started blowing that 30 amp fuse every time I shut the car down. I don't think it blows it until I shut the car off, because all my interior functions work, but once I shut the car off, everything inside dies and the car has no lights inside, nothing on the dash, no power seat/windows/locks/etc, no taillights, etc. I did notice that the headlights will still come up though...
If I put a new fuse in, the car starts right up and runs fine, but when I do anything that changes the flow (like rolling the windows down, moving my seat, putting it in reverse), the voltmeter flickers a little. Other symptoms that could be related: as long as I have had the car, the brake light just comes on and off as it pleases, it usually gets dimmer when I put the e-brake down but will come back on not long after. Also, I had some trunk leaks where water was getting on the taillight wiring, and the taillight failure light is on, although no bulbs are out and there is a new failure box and brake-switch installed.

Any ideas? Tomorrow I have some time to start looking through it, I am going to check if there is any battery drain when the car is off. Also, what all systems go through that fuse? I was going to follow the wires through the car and look for a place where the wires were melted or grounding. I also may just go to toyota and get the original 1.25b fusible link. Am I right that it's a bad idea to put my own piece of wire in for the fusible link?
Thanks for any advice!
Alex

 

[slightly_red_MA70]

I am having the same problem as you are, ive gone through 3 alternators since october. You really should go to Toyota and get that fusable link, the owner of my car before i got it put a normal piece of wire in there and it melted and lit my fuse box on fire.

 

[earlingy]

I am having the same problem as you are, ive gone through 3 alternators since october. You really should go to Toyota and get that fusable link, the owner of my car before i got it put a normal piece of wire in there and it melted and lit my fuse box on fire.

I saw your post, that did officially fix it?

 

[slightly_red_MA70]

I saw your post, that did officially fix it?

That and a new alternator. Mine was overchargind massively which caused that wire to melt. But now its started to undercharge again its really wierd.

 

[earlingy]

Toyota didn't have a fusible link. I put in a 30A auto reset circuit breaker, so now when it would blow the fuse every time i turn off the car, it just resets. Not perfect, I know there is still a short somewhere, but temporary fix while i look for the short.
Is there some other toyota parts place that does have it?

 

[earlingy]

Alright, took me a while, but I pulled each fuse in the fuse box and it would still blow that 30A at the alt. fuse. I shoudl have followed the engine harness since that is easier and removable, but since I am prepping a turbo swap, I figured the engine harness is already getting replaced. SO I followed the chassis wiring out from under the fusebox to the rest of the car. I unplugged it from all the harnesses, unwrapping, looking for a melted spot. I found lots of dirt and cleaned all that out, but what I also found was someone had very poorly rigged in my battery cables. The wire going to the alternator was like 3 wires, and they got smaller as it went toward the battery. Additionally, fat wire going to the starter was like a multitude of wires all rigged together.
I bought a new battery cable with larger wires, cut all that nasty !@#$ out, and cleanly soldered the new pretty things in. No more circuit breaker reset, no more blown alt. fuse. Yay!
My voltmeter still wiggles a little if I do at lot at once (roll the windows down with the lights on in reverse gets it down a volt or so).
Also all the heat shield on the wires going right next to the radiator were completely melted. I rewrapped those in heat resistant tape. Maybe something was getting hot from that?