Need burnt wire identity


#1

Car is 03 Impala 3.8- Not sure of scenario, (sister’s car,40 miles away) but no start, pictured wire burned through.
Need identity of wire and probable cause of burn- guessing fuseable link.
Thank you in advance for all information.


#2

The wire that is standing behind and to the right of the red cover does not appear to be burned. It appears to be cut. Will the starter crank the engine? Did the engine stall first or just fail to start?


#3

Nope- most definitely burned- I believe it is a fuseable link- talked to sister- she was starting car, big cloud of smoke from under hood, smell of burnt plastic.
Would help tremendously to know what this black wire is connected to and why the power surge.


#4

The red cover is hiding a positive battery terminal, probably for jump starting. Is the battery remotely mounted in this vehicle?

Why doesn’t she just have it towed to her mechanic?


#5

I believe you’re correct that this is the fusable link. That “wire” (it’s not a “wire” and should not be replaced with one, it’s a fuse in wire form) should run from the relay box to the + battery terminal. Your battery terminal will have one heavy cable going directly to the starter motor assembly and this fusable link, that goes to the fusebox. When you start the car, a relay in the box engages contacts that enable the starter motor solenoid circuit, and the solenoid assemblage engages contacts that allow current directly from the heavy battery cable to the starter motor. After the engine starts, the heavy cable becomes disconnected and the car’s ciruits operate through the fusable link.

The link blew for a reason. Something is drawing too much current. It can be a bear to find what, but a place that specializes in automotive electrical systems will have the experise to isolate the circuit drawing the excess current and troubleshoot the cause. Sometimes doing this requires removing inner body oanels and door panels and manhandling wiring harnesses, but something is probably shorting to ground and it’ll need to be fixed. They can also replace the link with one of the proper rating.

I’d recommend an automotive electricals shop for this one rather than a regular shop.

Good luck.


#6

It looks to me like the wire ran through the split in the strap for the cover. It wasn’t supposed to go through there. The plastic wore through the insulation and begin to cut into the wire. reducing its cross section. As the cross section of the wire at this point became smaller, it started getting hotter under load (current) at this one point, that further eroded the wire at this point. Eventually the wire became too small to handle the current and it burned in two. You can see the same damage occurring at the other point where it is passing through the slot.

The wire looks too thick to be a fusible link, unless it was made from a eutectic material. You can tell by cutting the wire about a quarter inch from the burn and see if it is copper colored or a dull grey. Also, eutectic wire is very flexible with no spring back, it feels like lead, which it is mostly. I think this is just a wire though.


#7

Thank you all for the reply s- Hard to give you all enough facts to draw conclusions on with out actually being where the car is to see exactly what is what.
I agree that something caused an overload and that cause must be found and that electrical rather than mechanical help is preferred. Not sure about the ‘wire’ being pinched in the red plastic cover slot but will look at that.
I’m only as good as my Haynes manuals (sans the electrical diagrams) and they don’t seem to address this particular area.
As for why my sister doesn’t “just have the car towed to her mechanic”, $. Don’t have it or a mechanic. Poor sisters are stuck with me.


#8

That wire is a fusible link made from 18 gage wire. That wire should go to the battery junction box located on the left strut tower connected to the same terminal for the positive battery cable.

Try replacing the fusible link and see what happens. I’ve seen fusible links burn up and when replaced never have another problem with it.

Tester


#9

Thanks again Tester- I’ll try that first-


#10

Be sure youo replace it with the prper part and not just wire. That link is protecting the rest of the circuitry in the car,as well as protecting against fire induced by an overheated circuit. You should be able to get the replacement at any parts store.

Sincere best.


#11

The GM wiring diagram discribes this fusible link as #18 gage wire, blue.

Tester


#12

Fusible links came in different gages and ratings, but they’re not the same as regular copper wire. Keith actually suggested a good way of determining if it is fusable link when he suggested scratching it. Fusible link won;t show copper. It’ll be the coloor of solder all the way through.

The good news is that links of the right gage cut to the right length with connectors already attached are readily available at parts store in bubble packs. The counter guy shoulld be able to look up the correct one.


#13

Thanks again everybody- Wont be able to get at it until Sunday-
Will let you know how it goes-