Fusible link?

[Rooster73]

I believe I burned up my fusible link. I’m new to working on rigs and I’m learning learning.

I pulled out my steering column to replace my clutch/brake pedal assembly. In the process I smelled smoke and noticed the rubber spacer between the power steering box and the lower steering shaft was burning.

No idea why.

When I got everything put back together I have no power. No ignition. No lights. Nothing.

I believe the wire on the firewall in the engine compartment next to the brake booster is where the fusible link is??? Either way, there is a wire there that’s burned through. I have power to that little block.

What on earth would have caused that rubber to start on fire? I’m sure there was oil on it.

What role would removing the steering column play in starting the fire. It was small and went out when I blew on it, but I’m just puzzled.

Thoughts???

Thanks.

 

[CalSgt]

I believe I burned up my fusible link. I’m new to working on rigs and I’m learning learning.

I pulled out my steering column to replace my clutch/brake pedal assembly. In the process I smelled smoke and noticed the rubber spacer between the power steering box and the lower steering shaft was burning.

No idea why.

When I got everything put back together I have no power. No ignition. No lights. Nothing.

I believe the wire on the firewall in the engine compartment next to the brake booster is where the fusible link is??? Either way, there is a wire there that’s burned through. I have power to that little block.

What on earth would have caused that rubber to start on fire? I’m sure there was oil on it.

What role would removing the steering column play in starting the fire. It was small and went out when I blew on it, but I’m just puzzled.

Thoughts???

Thanks.

Yes the junction block just to the left of the brake booster should have a fusible link attached to it (IIRC there’s two fusible links there, and another hooked to the starter)

As for the fire I’m not sure I understand exactly what burned, how’s about a picture.

If you dropped the column and replaced the pedal bracket You may have pinched a wire causing a direct short. I’d definitely recommend inspecting every spot a wire could have been damaged before replacing the fusible link.

 

[Rooster73]

I thought the pictures posted with my first post. I’ll try again. Hopefully they come through.

 

[Rooster73]

Yes the junction block just to the left of the brake booster should have a fusible link attached to it (IIRC there’s two fusible links there, and another hooked to the starter)

As for the fire I’m not sure I understand exactly what burned, how’s about a picture.

If you dropped the column and replaced the pedal bracket You may have pinched a wire causing a direct short. I’d definitely recommend inspecting every spot a wire could have been damaged before replacing the fusible link.

I’ll check for pinched wires.

Would it be possible that there was a grounding issue somehow through the column when I was pulling it? The small fire happened while I was removing all the hardware to pull the column out. I don’t remember if I had started disconnecting wiring connectors yet or not.

I think I’ll check grounds on the truck too. I’m just not sure how many and where they all should be. Any guidance there?

 

[RaisedK5]

Chances are there was a pinched wire in or around the column and was shorting to ground thru the rag joint/steering box while the top of the column was loose.

 

[CalSgt]

That’s called a rag joint. My guess is you shorted a wire to the steering column…

The current flowed down the column to the steering box to find ground. Not sure if the rag joint is steel belted but the current passed across it or through it and burnt it up until the fusible link blew. If the column is unbolted from the pedal bracket the steering box would be the only other grounding point, it’s isolated from the firewall and the shift linkage with rubber grommets.

It’s possible the column contacted a wire while you had it loose, the ignition switch is right on top of the column and has large gauge wires that are constantly hot with voltage. They are not fused in the panel on the firewall the only protection for that wire is the fusible link.

Start searching for evidence of damage to the ignition switch bundle of wires and anything near where you were working

 

[Hew Klaus]

Where did you find a replacement? Mine was burnt as well. Looking online and no luck.

 

[75gmck25]

What are you trying to replace? I believe the standard GM fusible link is a 14 gauge link for a 10 gauge wire. You should be able to get one at any parts store. https://www.rockauto.com/en/moreinfo.php?pk=623530

Another good source is any junked GMT400 truck, since the wires and fusible links are connected to an electrical bus bar up on the firewall in the engine compartment. Very easy to reach and pull off a junked truck.

Fix the short first, and then cut out the burned section of wire and splice in the new fusible link.

 

[Sad Sack]

When doing work under the dash disconnect the battery.

 

[Goldie Driver]

Yeah, I mean you are right ...

 

[Sad Sack]

Yeah, I mean you are right ...

Someone had to say it…

 

[Radiohead]

It's easy to forget.

 

[Radiohead]

What are you trying to replace? I believe the standard GM fusible link is a 14 gauge link for a 10 gauge wire. You should be able to get one at any parts store. https://www.rockauto.com/en/moreinfo.php?pk=623530

Another good source is any junked GMT400 truck, since the wires and fusible links are connected to an electrical bus bar up on the firewall in the engine compartment. Very easy to reach and pull off a junked truck.

Fix the short first, and then cut out the burned section of wire and splice in the new fusible link.

NAPA has rolls of it, but they're pretty proud of it.

 

[75gmck25]

Fusible links are always 4 awg sizes smaller than the wire it protects.

When I switched to a larger gauge charge wire for my alternator, I believe the one i pulled from a GMT truck was 8 gauge with a 12 gauge fusible link, as compared to my Squarebody 10 gauge wire with a 14 gauge fusible link.

The OEM GMT truck links are easy to see because they have a plastic barrel (like a sealed fuse holder) and it has the size stamped in it. However, the link size is in square millimeters, not awg wire sizes. This article explains how to convert between awg and mm sizes. https://rvelectricity.substack.com/p/a-deep-dive-into-fusible-link-wires

 

[Jgonick]

However, the link size is in square millimeters, not awg wire sizes.

I'll just add this here to make it easy..

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