Truck won’t turn on

[Rudy Euresti]

My dad put on the battery into my truck after using it on his truck. But when he put it onto my truck, he accidentally put the cables reversed. I put them on correctly and now the truck doesn’t turn on. I checked the battery with some jumper cables, by quickly touching them together, there wasn’t a spark at all. I’m hoping it’s only my battery that died out. I saw that I don’t have a fusible link. If that’s what’s in this picture. If it’s not only my battery, what other problems could come up? I read that it could’ve ruined my alternator as well? The voltage regulator.

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[1987 GMC Jimmy]

Fusible links are the main concern when that happens, but I’ve done it on a dual battery vehicle where the second battery goes in backwards, and I wasn’t paying attention. It was only for a second, and all it did was shoot molten battery terminal at me. The battery was still good, and nothing else was damaged.

It’s too hard to speculate because sometimes nothing happens and sometimes there several weird gremlins afterward. You need to get a fresh battery and have your test light or DVM on standby in case something got fried. You’ll check your alternator output at the back of alternator and at the battery to make sure it’s all getting there.

 

[Rudy Euresti]

I took my battery to get charged and tested. My headlights and such turn on but nothing happened when I turn the key. That buzz from having the key in , isn’t there also

 

[gotyourgoat]

Sounds like there might be some blown fuses. You mentioned the headlights work, do the other always hots like the cig lighter and hazards work?

 

[75gmck25]

The stock power setup on my '75 connects the positive cable to the starter lug. From that lug there are also 2 smaller wires with fusible links on the starter end (10 gauge wire, I believe). One wire runs up to the alternator BAT terminal (to charge the battery), and the other wire, which powers the fuse box, runs up and over to the junction that is next to the brake booster.

You should see the incoming power wire running straight up and connecting to the junction point on the firewall. The first few inches of this wire is a fusible link, and it may look just like the rest of the wire. If the power is hooked up backwards it will burn this link internally and eventually burn the outside covering. However, it might break internally and not have visible damage on the outside.

I've made the battery hookup mistake myself and all it did was burn out that fusible link. The alternator seemed to survive fine. YMMV.

Bruce

 

[dvdswan]

The wires cut at the firewall are for your HVAC system in the engine compartment. IIRC.

 

[Rudy Euresti]

Is this suppose to look like that?

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[Rudy Euresti]

The stock power setup on my '75 connects the positive cable to the starter lug. From that lug there are also 2 smaller wires with fusible links on the starter end (10 gauge wire, I believe). One wire runs up to the alternator BAT terminal (to charge the battery), and the other wire, which powers the fuse box, runs up and over to the junction that is next to the brake booster.

You should see the incoming power wire running straight up and connecting to the junction point on the firewall. The first few inches of this wire is a fusible link, and it may look just like the rest of the wire. If the power is hooked up backwards it will burn this link internally and eventually burn the outside covering. However, it might break internally and not have visible damage on the outside.

I've made the battery hookup mistake myself and all it did was burn out that fusible link. The alternator seemed to survive fine. YMMV.

Bruce

I’ll make sure to check those wires tomorrow. Hopefully that’s the case

 

[Rudy Euresti]

These?

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[Rudy Euresti]

Accidentally cut into wire when i was breaking off the melted plastic. They’re not melted / burned.

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[Snoots]

That's a definite problem. Trace both ends of those wires.

 

[Rudy Euresti]

That's a definite problem. Trace both ends of those wires.

one is to the alternator and two go to the firewall i believe. to that bulkhead? i think thats what its called.

 

[Snoots]

one is the the alternator and two go to the firewall i believe. to that bulkhead? i think thats what its called.

Yes. Replace, don't repair, that entire length of wire. You can add a 30amp in-line fuse to that. I'd use a 12AWG wire minimum. The higher wire thread count the better (finer wire inside) the insulation.