truck won't start - fusible links?

[AJMBLAZER]

SEE BOTTOM POST

This is why I hate working on electrical stuff.


Was removing my 24v slave connector today and well...sorta got ahead of myself. First chance I've had to work on it in a while and it was going pretty smoothly.

Had the connector itself unbolted from the front of the truck and was starting to work on the ends of the cables where they meet the terminal strips on the passenger side firewall in the engine bay. Got the positive one loose and then started on the negative that goes to the lower strip...

...get one good crank on it and I touched the threaded portion of the upper strip all the way towards the driver's side...


...did I mention I forgot to disconnect the batteries?

Yeah...so as I'm writing this the batteries are now freshly disconnected but I'm sure I need at least a new front battery. Shame as these are only a few months old.
Anyways, sparks, flame, and gases emanated from the positive terminal on the front battery and scared the crap out of me. I know I need a new connector there at the minimum now. Thing is fubar. Whole post burnt right up and took a bunch of the inside of that connector.
Meanwhile the ratchet is welded to the terminal strip and I need to go chisel it off.

So what did I likely fry here? The connector and wire going from the front positive is hot to the touch obviously but nothing else seemed hot, sparky, smokey, or burnt.


Crap...dumb da dumb da dummmmmmmmmmmb!

 

[Crash_AF]

RE: What did I just screw up (electrical related - with pics

Battery is toast for sure... luckily it didn't explode. The cable end might be able to be salvaged, but if you have the capability to get a new one, you'd probably be better off replacing it.

The ratchet is also toast... I'm sure the guts are welded together now so it might make a good breaker bar... LOL

Other than that, everything else should be fine.

Later,
Joe

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

Thanks.

Just tested the rear battery and it seems fine with 12.57 volts. Shouldn't have been any way for it to be damaged...right? I'm horrible with electrical stuff.

Yeah, about to take my ginormous cutters to the front positive lead and just snip it off. Can always pick up a new one at the parts store when I take the battery back.

So basically what did I just do and why shouldn't it have taken anything else with it?

 

[Crash_AF]

RE: What did I just screw up (electrical related - with pics

You created a dead short between the positive and negative battery terminals with no resistance. If you think of electricity as water, you just knocked a hole in the dam and all of the water rushed out at once. Since the connection between the positive terminal on your battery and the clamp wasn't perfect, this created resistance to the flow and that resistance caused heat, which melted the lead of the terminal before the clamp. The short was between the two terminal boards, which were only connected to the batteries with no other items between them, thus only the ratchet was damaged on the short end and the terminal on the battery end.

Later,
Joe

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

Okay, got the idea. Thanks again.


The good news is that Advanced is perfectly willing to replace the battery even with me saying it's demise was my fault.


Life lesson...always disconnect the battery(ies).

 

[ida34]

RE: What did I just screw up (electrical related - with pics

I would also check for any other short to ground as you may have melted some insulation in a place you can't see. You are probably good but I would check before arc welding, I mean, putting the new battery in.

 

[CCATLETT1984]

RE: What did I just screw up (electrical related - with pics

actually you dont need to disconnect both batteries, just the ground from the body to the front battery, without a ground path your fine

 

[thedeliverator]

RE: What did I just screw up (electrical related - with pics

I've installed these:
http://www.autoaccessconnect.com/toppobaswwib.html in all three of my vehicles to make disconnecting the batteries easy. It's a handy way to avoid situations like AJMBLAZER's. Also a fairly effective anti-theft measure when combined with a padlock on the hood.

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

Okay, so my project spiraled quite a bit and took a while longer. Finally got enough of the other jobs done to slap the batteries back in and my cobbled together new forward battery tie down. Hooked the harnesses back up and...no juice. Dash won't light up or anything. Both batteries are at around 12.5 volts so they're good. Nothing LOOKS cooked but that doesn't mean much.

Thoughts?

 

[CCATLETT1984]

RE: What did I just screw up (electrical related - with pics

check the fusible links on the drivers side of the truck, near the glow plug relay. you may have fried them.

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

So how does one check these and replace them?

How many are there total?

They're the blue sections of wire aren't they?

 

[CCATLETT1984]

RE: What did I just screw up (electrical related - with pics

yup the sections of blue wire, if they have the insulation burned of or feel brittle inside, replace them.
As i recall there are three or four of them in a group on the drivers side of the firewall below the glow plug relay (maybe five).
Also check the fusible link on the main 12v wire going from the battery cable to the small distribution block on the firewall. and of course your fuses.

Luckily the way they over-engeered the system in this truck, its quite survivable.

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

What gauge wire should be used?

Just cut them out and then solder new lengths back in?

 

[CCATLETT1984]

RE: What did I just screw up (electrical related - with pics

get new fusible links from the parts store. cut them out and crimp the new ones on. solder will mess them up due to the heat.

 

[AJMBLAZER]

RE: What did I just screw up (electrical related - with pics

So something like these then?:

http://www.napaonline.com/MasterPag...rdCat=Fusible+Link+Wire+-+Universal&VehCode=N

 

[CCATLETT1984]

RE: What did I just screw up (electrical related - with pics

I used these
http://www.napaonline.com/MasterPag...rtNumber=784693&Description=Wire+Fusible+Link
except they were orange and 14ga.

 

[AJMBLAZER]

Having a hard time identifying the fusible links as there's the blue wires...and then several other color wires right near both locations that look just like them only in different colors.

I've attached some pictures.

None seem to be crispy, burnt, or stiff...however I'm not good with electrical stuff so I could be totally missing it.

Which are the fusible links?

In the bottom picture the rightmost terminal that is visible is the one I grounded the ratchet on and then welded it to. Is that a fusible link coming off of it? Looks like the others.

 

[AJMBLAZER]

Oh yeah, the black connector that most of them have - is that a reusable connector or part of the fused assembly or something? Do I just cut that off and replace it with the NAPA part at that point?

 

[CCATLETT1984]

all the wires with the black connector are fusible links. the different colors are different ratings. you cut them off and crimp on the new one on the wire.

 

[AJMBLAZER]

Okay, did some checking with the multimeter. I've got 25v at the rear battery, at the upper right terminal that I mentioned above, and at the "in" connection on the glow plug relay (has red wires in the second from bottom picture above).
I have nothing on the out relay below it (orange dual wires) but while probing around in open spots in the fuse box I found a constant 25v source.

Any thoughts?