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fusible links by Csjag
Started on: 03-16-2015 06:21 AM
Replies: 12 (754 views)
Last post by: RWDPLZ on 03-18-2015 09:06 PM
Csjag
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Report this Post03-16-2015 06:21 AM Click Here to See the Profile for CsjagClick Here to Email CsjagSend a Private Message to CsjagEdit/Delete MessageReply w/QuoteDirect Link to This Post
When I first got my Fiero and before I even knew about this forum and knew what I was doing I bypassed some fusible links for the headlight circuit. I would like to put them back. Does anyone know of a source for them and what rating the links for the headlight have? Thanks
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theogre
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Report this Post03-16-2015 12:13 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
See my Cave, Fuse Links notes

source at most parts stores

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Raydar
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Report this Post03-16-2015 05:47 PM Click Here to See the Profile for RaydarClick Here to Email RaydarSend a Private Message to RaydarEdit/Delete MessageReply w/QuoteDirect Link to This Post
Is it ever acceptable to replace them with fuses? (Thinking sealed fuse holders. Not the "push and twist" variety.)
Any idea on value?

Thanks.
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cmechmann
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Report this Post03-16-2015 06:59 PM Click Here to See the Profile for cmechmannClick Here to Email cmechmannSend a Private Message to cmechmannEdit/Delete MessageReply w/QuoteDirect Link to This Post
Ah the days when replacing fuse link wire was normal. The biggest issue was getting good quality crimp terminals.
Most cars use MAXI fuses now. For years seen many people replace an alternator in Fords when the "shark egg" fuse would be open.
I would like to replace my fuse links with a remote MAXI fuse box if I could rely on the connectors. The early 90s Cavaliers had a small under hood box that would work nicely, but would have to cut out the relay section. Don't see many inline fuse holders that are beefy enough. Except for those over priced holders they sell at audio system outlets and they are too bulky to run several near each other.
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theogre
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Report this Post03-16-2015 11:11 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
 
quote
Originally posted by Raydar:
Is it ever acceptable to replace them with fuses? (Thinking sealed fuse holders. Not the "push and twist" variety.)

Some yes. Most no.
Big problem is Fiero engine bay is a Very wet area because of the vents etc. Most Fuses and weather/water resistance holders just won't last. Is much easier to "water proof" a fuse link.
Many cars using Maxi fuses have them mounted high in the engine bay and hood etc keeps most water out of the bay and fuse "box."

Related issue... Basic ACDelco and others brands Spark plugs rot out because bay is very wet in many areas in the U.S. Many use Platinum etc plugs on Fiero because the shells are Nickle/whatever coated to prevent rusting. I've use cheap ACD and Autolite on most cars and never seen same problem as I see on Fiero engines.

"Any idea on value?"
Sorry... ECM standby power only needs 1-2 amp fuse but Too many things affect the answer for others.

Many think that FL and Maxi Fuses are there to protect devices... Wrong.
Most FL are used to stop 400-700 amp or more from battery on a short circuit.
Is why most FL and Maxi fuses are in the engine bay close to the battery and alt.
Example:
Wire to HL goes thru the whole car... You can short out that wire and blow Link B w/o affecting anything connected to the line. If Link B wasn't there, the whole wire will see full output from the battery and That can easily cause a fire in the cabin!

FL/"shark egg"/maxifuse in the Alt circuit is same... Dead alt can short out the battery.

[This message has been edited by theogre (edited 03-16-2015).]

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thesameguy
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Report this Post03-17-2015 01:00 PM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
I would personally always replace fusible links with fuses. IMHO, fusible links are dangerous - any systems that is designed to burn when it fails isn't a great idea. Besides the obvious (albeit minimal) risk of fire there is the risk of collateral damage from melting metal or insulation, and fusible links aren't exactly accurate - they fail "at or around" a certain amperage.

There are lots of ways to tackle fast-blow fuses in unfavorable environments -

http://www.waytekwire.com/i...R-20A-32V-MINI-FUSE/
http://www.waytekwire.com/i...OLDER-FOR-MINI-FUSE/
http://www.waytekwire.com/i...41/MINI-FUSE-HOLDER/

These are all environmentally sealed and use ATM ("mini") fuses, so they'll support up to 30a... obviously choose the right pigtail if you need 30a!

Another approach is these:

http://www.waytekwire.com/i...TRIBUTION-CONNECTOR/

With the proper top and seals you can make them weatherproof and they hold up to four ATM fuses. I use these on my Falcon to fuse the headlights:



I also use them without a cover to fuse most of the electricals (tail lights, dash lights, blower, etc.)



All you need is a $30 weatherpack crimper and a handful of metripack terminals (also available from Waytek).
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Gall757
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Report this Post03-17-2015 02:05 PM Click Here to See the Profile for Gall757Send a Private Message to Gall757Edit/Delete MessageReply w/QuoteDirect Link to This Post
Your excellent pictures clearly show why the manufacturer did not do this in the first place.....$$$. Fusable Links are extremely cheap, and weather does not effect them (real weather,,,,not California weather... ), so, naturally, that is what GM went for. I have yet to see a failed link that burned through it's cover, but It probably has... The biggest problem I see is getting the proper size replacement for a bad one.

[This message has been edited by Gall757 (edited 03-17-2015).]

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thesameguy
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Report this Post03-17-2015 02:31 PM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
Replacement links are actually super easy to source - they are sold as a wire size... eg, "14ga fusible link" is a fusible link for protecting a 14ga wire. Any auto parts store will have them. You just crimp them in.

Cost is definitely a motivator, and it's crazy that GM protected something like a headlight with a fusible link. Well, maybe not crazy. The big advantage of a fusible link vs. a fuse back in the '80s was its tolerance... they can take amp spikes that a fast blow fuse cannot in a sealed package that wasn't easily replicated. Maxi fuses & AMI/AML/AMG/Mega fuses didn't exist until the '90s. Using a fusible link to protect the battery (from the alternator, as Ogre said) was about the only approach. It's possible they used a fusible link on the headlight motors knowing that as they aged there would be a big inrush current that could pop an ATC fuse. Today, I'm sure they'd use a maxi. So, *maybe* it wasn't cheaping out... maybe it was the only reasonable choice.

(FWIW, in the picture I posted next to the headlight fuses is a big plastic bracket. That's an Mega fuse holder - the fuse protects the battery from the car's 130a alternator.)

I just can't endorse buying fusible links anymore, not with all the widely available, superior solutions. I've actually never had a fusible link fail on me, but the previous owner of my XR4Ti had one fail and it got so hot it melted about 10 wires that were all bundled around it and shorted out the ECU. A $1 fusible link caused hundreds of dollars worth of damage in moments. Just not worth the risk. Hop on waytekwire.com, buy some permaseal crimp-on butt connectors and a weatherproof fuse holder and put some modern circuit protection in place!

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theogre
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Report this Post03-17-2015 04:42 PM Click Here to See the Profile for theogreClick Here to visit theogre's HomePageSend a Private Message to theogreEdit/Delete MessageReply w/QuoteDirect Link to This Post
Link B is same as A E and F, stop battery from dumping 400+ amps in a short circuit.
Link C, D is because Stalling Amps on the Gen 1 motors at end of travel.
Gen 1 Stalling amp draw can easily blow normal fuses. If they have other issues even more so.

G1 HL motors have circuit breakers built in to the motors. The problem is Breaker Auto Reset is why G1 system can kill the battery.
G2 Module have fuses for that version.

HL bulbs uses a thermal circuit breaker in the HL switch.
Other lights use tail light fuse in the fuse box.

Fire? Please... W/ exception of link H... Most FL in Fiero (and Many other cars) are in places that if they blow little to nothing else get damage. GM pulled most of links C and D out of front wiring harness. If Link H blows then might get damage to C500.
FL insulation are made to smoke but not burn and keep wire inside of insulation.
Are rules to make them... I forget exactly what SAE etc doc covers their construction.

I've worked in cars for 30+ years. I've seen only two link blow.
1 was 73 Ford in ~ 1982. Weather got to the copper and ate the link until it blew. Area of "copper" after the link blown was heavy green, many strand were gone.
1 was 70's or early 80's TA... Like 84 Fiero, FL went to starter solenoid. Heat, Weather, and Road Salt can kill any wire to that spot. Blown FL was common problem and why GM switch to FL near to battery in many vehicle starting w/ 85 model year.
Both keep the wire from hitting other parts.

If car have them then just replace w/ same.
For one, Most people do not have skills and/or tools to properly replace them w/ Maxi Fuses.
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thesameguy
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Report this Post03-17-2015 05:43 PM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
You can do whatever you want, but there is a reason nobody uses fusible links anymore. They can cause collateral damage (even if rarely), their smaller gauge results in necessarily higher resistance, they are annoying to track down and replace, and they are an imprecise method of circuit protection. Whether a person has the ability to install an alternative solution is another matter* - fusible links are still demonstrably an inferior and outdated solution.

* If you can't operate a wire stripper and crimper, you probably have no business working on automobile wiring in the first place.
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cmechmann
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Report this Post03-17-2015 07:53 PM Click Here to See the Profile for cmechmannClick Here to Email cmechmannSend a Private Message to cmechmannEdit/Delete MessageReply w/QuoteDirect Link to This Post
I was going through a bunch of sites last night. The only aftermarket ones I saw that I would trust were at marine sites.
Ogre is right about the moisture problem. There were a few models of Kia/Hyundai that the underhood fuse box looked fine until you turned them over and took the bottom cover off. Only to find a green Chia pet growing inside. Because the copper rails were so eaten away, the only good repair was to install a new under hood harness and fuse box. Then fill the underside of the new box with protective electrical grease. Most customers just offed the car.
2 reasons I like the marine boxes. 1 they have a few that use bolt on terminals. Instead of spade terminals. 2 they have better protection for moisture problems.
Even after GM started using maxi fuses, for a good while they still used a fuse link for the alternator.
The cars that I did a lot of fuse link repairs, were 70s/early 80s GM v6, v8s that had air injection. Gm tried to do a good job of putting the wires in a shield over top the starter. The A.I.R tubes would quickly rot out blowing exhaust onto the harness where it ran down on the back of the engine causing the shielding to melt. Or they would have a leaking reed/check valve. Especially the ones that had a cat converter tube. Then fry fuse links. It got so bad that GM changed the design of the A.I.R manifolds. The replacements would only have one port for each bank and have plugs that you install in the exhaust manifolds for the ports that were no longer used. Seemed the Chevy 229/3.8 were the worst for that.
For the most part. It wasn't a failure of the fuse links rather than design of the harness routing.
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Report this Post03-18-2015 12:56 PM Click Here to See the Profile for thesameguyClick Here to Email thesameguySend a Private Message to thesameguyEdit/Delete MessageReply w/QuoteDirect Link to This Post
A proper Metripack or Weatherpack installation is sealed against the elements, with both the cap and the wires into the housing having seals on them. If Kia was having a problem with moisture in connectors, it was because they were using cheap materials. You'll never find a GM car with a proper Metripack or Weatherpack connector with moisture issues. I mean, that's the reason they're called Weatherpack!

Maxi fuses are not sufficient to fuse a modern alternator. Maxi fuses are only good to 80a, and those are newer, special fuses. Conventional Maxi is only good to 60a. To fuse an alternator, you need an AMI or Mega fuse, which have ratings up to 300a IIRC. You generally want to use a fuse that's +50% of the max output of the alternator, and Megas increment in 25a. So a 75a alternator would need a 125a fuse, a 130a alternator a 200a (maybe 175a) fuse, etc. You can't get to those numbers with Maxi fuses, so until Megas came on the scene GM (and others) continued using fusible links. It's fair enough, there wasn't a better choice. But, now there is.

I can't speak to the marine boxes you're talking about, but I certainly wouldn't recommend using spade terminals on a fuse box today. There weren't options in the past, but today there are *many*. A positive-latching, sealed housing is the only way I'd go. Again, Metripack or Weatherpack would be great options. The terminals latch into the housings, and the housings latch to each other. It's an excellent mechanical connection. If you're not interested in buying the correct crimping tool ($30+, depending on how fancy you want it to be!), you can buy pre-assembled housings and then just use a permaseal (et al, some sort of seal) butt connector to splice the housing into your existing wire.

Here is how you assemble Weatherpack, note the green seals on the housing and on the wires to keep moisture out:



Metripack can be assembled in a similar fashion - that's how the fuse holder on my Falcon posted above is assembled. It's completely weather tight, and there are no spade terminals to become detached. It's all positive-latching, no room for error or accidents. It's good stuff.

[This message has been edited by thesameguy (edited 03-18-2015).]

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RWDPLZ
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Report this Post03-18-2015 09:06 PM Click Here to See the Profile for RWDPLZClick Here to visit RWDPLZ's HomePageSend a Private Message to RWDPLZEdit/Delete MessageReply w/QuoteDirect Link to This Post
Weather Pack systems overview, with some part numbers:

http://www.waytekwire.com/d...erPackSalesSheet.pdf

Overview

http://catalog.delphi.com/c...chure/dcs_170011.pdf

Spec sheet example

http://catalog.delphi.com/c...12010184_sheet_1.tif

Crimping 12020801:

http://catalog.delphi.com/c...InformationSheet.pdf

You can find them on Mouser

http://www.mouser.com/

Fusible links are still used, just not the wire type fusible links. J-Case are pretty common.

http://www.littelfuse.com/~...ket_catalog_2013.pdf
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