eli-sky

89 with a 3.0. i was driving and all of a sudden it just shut off. looked under the hood and a wire from the positive terminal had been shredded. i was under the impression this was a fuseable link running to my alternator( according to the factory manual) but am unable to find the other side of this wire.
any ideas here would be awesome.

YFZsandrider

I don't know if it would allow things to just go dead while driving... but battery terminals, if they become dirty can give that same "absolutely no power" condition.

eli-sky

even trying to boost it did nothing. i guess ill attempt a battery swap. i just wonder what this other wire was that came off my positive terminal... it seems to be the cause but i cant find where it went.. or what it is

abecedarian

Pics?
May be the wire to the fuse block.

bugs1961

There should only be two wires going from the battery positive terminal. The cable to the starter and a power wire to the fuse/relay block behind the battery. The wire from the alternator goes to the fuse block and connects to the large ALT fuse (sometimes called a fusible link).

The wire from the battery to the block has a short section of special wire that is also called a fusible link. The inline fusible link wire has special, thick insulation that is designed to melt the conductor in an overload but not melt the insulation. The insulation will bubble and distort but not melt or burn. The fusible link is typically two gauge sizes smaller than the wire it will protect and is about 2" long. Our trucks use a wire that is 2mm squared which equates to 14 ga wire. Auto parts stores sell this fusible link in one or two foot sections for replacement of burned links.

Connect about 2" of fusible link wire to the battery and join 10ga wire from the link to the fuse block. This will protect the block and wiring in the event of an overload and prevent a fire.

eli-sky

Well if thats the case i must have missed something..... the first thing i did was take the fuse block off the fender wall to check underneath it. tomorrow this shall be resolved! thank you for your assistance. i will update when solved.

YotaTron88'

Easy to track prob. Get a good LED light tester...not one of those "airbag blower ones". Ground one end and start probing to see where you have 12v+. If your getting power in and out of you fuse box then thats not the prob. Do the dash lighs come on when you turn the key on?, the headlights? Don't look at small fuses....test both side with the tester. If one side is one and the other dead.....the fuse is pooped. the If dash lights up (oil light, brake light, the lights right before you start it,) come on than your not getting ignition past your ignitin switch...your key. Probe the thick 12 gauge (12awg) wires under the dash running up the steering collum. Get the wire colors off some stereo hookup site, or the manual. Do you have power there? If everything is dead then you blew a fusable link. Just keep testing and you will find the prob. Test at the alternator and starter.....

jpmountainboy

maybe check the 80 amp fuse again to. I know you said you checked em, but that one is hard to tell, it happened to me, but on very close inspection (the plastic lid actually came off) it looked barely / maybe blown. replaced it and fired right up. I had shorted the alt wire while on accident on a 3.4 swap.
good luck.

eli-sky

so i believe i need to go from this connector to

this style connecter for my battery.
how big of a wire do i use?? the last one was a bit smaller then my other battery cables. Do i go from a 4 gauge to a small one just before the connector on the fuse block?(top picture). electrical is really not my strong point. i have no idea how it was set up before other then it had a 4 gauge wire coming off the battery.
any help would be deadly. thank you!

bugs1961

Go back and read my post above (#5) and you will be fine.

Kiroshu

Clean battery terminals too.

eli-sky

WELL.... that now solves everything and i didnt really need to post pictures. im still confused why the previous wire was 4 gauge....

bugs1961

Here is a photo of my wires. The 4 ga wire in your photo is to the starter and the same wire on my truck is circled in blue. The wire I circled in red is the fusible link section on the factory fuse block wire and the arrow points to the wire going to the fuse block. The factory wire is covered by a plastic sheath for protection so it looks larger than it is.

Read this post https://www.yotatech.com/forums/f116.../#post51139519 and you'll get a pretty good idea of the electrical theory needed to determine what size wire you'll need.

Here is what I came up with:

You want a max of .5v drop in any power wire due to resistance in the wire itself. (Wires have resistance and too small wires have too much resistance and get hot.)

Ohm's Law is: V = I (current) x R (resistance)

The alternator is protected by an 80 amp fuse, and that is the largest fuse in the truck. Under any circumstance there shouldn't be more than 80 amps in the wire to the battery (if all the alternator output went to the battery, which doesn't actually happen), but I'll use 90 amps for a little pad.

The chart of wire resistance attached in the link above gives a resistance of 1.1 ohms per 1000', or .0011 ohms per foot for 10ga wire. The wire from the battery to the fuse block is a little over a foot long but I'll use 1.5 feet to be conservative. So there is .00165 ohms of resistance in 1.5' of 10ga wire.

Now I know how to calculate how much voltage will drop in the wire if there is a short in the alternator wire. (Worst case as other circuits have smaller fuses)

V = 90 amps x .00165 ohms
v = .15 volts This is a safe and efficient wire that won't cause any problems.

The only other concern is if the 10ga wire itself chafes against something that is grounded and shorts out. The fusible link is there to protect the 10ga wire from starting a fire because it will safely melt and open the circuit before the 10ga will.

This is a lot more information than you probably wanted to know but I needed to show how I came up with the recommendation on the wiring, so you can sleep well at night .

Take care,
Bugs

eli-sky

ok so the little wire the is supposed to melt is 12g. its the only thing crappy tire sells. would using any 14g wire be fine? would it be fine to use to 10g to the 12g or would it be better to use 8g and the 12 g link.

eli-sky

by the way bugs, thanks for all your help. and all else

bugs1961

No problem! You don't want to use regular wire for the fusible link because the link is designed to melt during an overload, before the rest of the wiring can melt. Regular wire (of any size) will potentially start a fire when the insulation starts burning during an overload. You can buy special fusible link wire at Checker, Autozone, Napa, etc. Look for a package labeled "Fusible Link". The actual wire will be 14ga but the insulation is much thicker than normal wire and looks like 12ga. This special wire needs to be 2" to 3" long and be between the 10ga wire and the battery in order to fully protect all the wire in the truck. Use a crimp type butt connector to connect the link to the 10ga wire and a crimp type loop connector for the battery connection. Covering the whole link and connectors with wire shrink wrap will keep the corrosion away for long term reliability. Take care,
Bugs

YotaTron88'

Make sure an SOLDER the connections! Those crimp things hold alot of resistance, they fail a lot, and they look like an amatuer job. If your soldering new terminals on your battery wires use a torch and heat the conneter untill solder gets sucked into the wire....

bugs1961

Ya, for sure, if you can solder the connections, do it!

eli-sky

i had all intentions to solder! seen many hack jobs that didnt amount to much, gunna do it right the first time this should be wrapped up nicely tomorrow. cheers

eli-sky

holy hell
so its all done.
runs like a heap!
want pictures? well ok


it has since been cleaned of snow