Blade Fuse with LED that glows when fuse blows

aka_juffa · Postby **aka_juffa** » Wed Feb 01, 2012 9:54 am

As per my previous thread re blowing a fuse in my NA8. I dropped into Jaycar yesterday to get some extra blade fuses. They have a pack of 6 fuses for $5.95, with various amperages. These fuses have a LED built in that glows when the fuse blows. You can also buy individual fuses at $1.20 each.

http://www.jaycar.com.au/productResults ... rm=KEYWORD

IMHO this is a great idea as the blown fuse will be obvious. Saves time if you are like me and your under dash fuse box cover is missing, you don't have to work out which fuse is the culprit.

Just thought I would share.

J.

Bauer · Postby **Bauer** » Wed Feb 01, 2012 4:24 pm

As someone who changed a lot of fuses in his time as a mechanic in the 80's and 90's, that is a great idea

good share

hks_kansei · Postby **hks_kansei** » Wed Feb 01, 2012 4:28 pm

How do they work?

I mean, a fuse blows to cut current to save whatever set it off.

If there's a light there, that means the light is completing the circuit?

Unless they mean the fuses light up, and turn off when one blows?
That makes sense.

Light lit = circuit.
Fuse blows, circuit broken, light goes out.

aka_juffa · Postby **aka_juffa** » Wed Feb 01, 2012 9:37 pm

hks_kansei wrote:How do they work?

I mean, a fuse blows to cut current to save whatever set it off.

If there's a light there, that means the light is completing the circuit?

Unless they mean the fuses light up, and turn off when one blows?
That makes sense.

Light lit = circuit.
Fuse blows, circuit broken, light goes out.

I know, it doesn't make sense to me either. The packing clearly states When they blow they glow....now if you give me $1.20 I will test one out for you :mrgreen:

Guess I will know more in the next few days when I can investiage why the fuse is blowing and replace most of the current fuses with the new ones.

J.

Zcootz · Postby **Zcootz** » Thu Feb 02, 2012 12:30 am

When the fuse is intact there is no voltage difference between the two fuse contacts, when the fuse blows you get the voltage difference which is what the LED needs to light up.

aka_juffa · Postby **aka_juffa** » Fri Feb 03, 2012 9:09 am

Thanks Zcootz. Makes more sense now. I can confirm that when plugged in the new blade fuses do not glow. I even tried to blow a 5 amp fuse to see one in action. I plugged the 5 amp fuse into the cigar lighter circuit, and while the lighter did its thing it didn't blow, which either means that the lighter uses less than 5 amps, or the fuse is not working as designed.

Interesting as the orignal fuse for that circuit is 15 amp.

J.

greenMachine · Postby **greenMachine** » Fri Feb 03, 2012 11:28 am

aka_juffa wrote:Thanks Zcootz. Makes more sense now. I can confirm that when plugged in the new blade fuses do not glow. I even tried to blow a 5 amp fuse to see one in action. I plugged the 5 amp fuse into the cigar lighter circuit, and while the lighter did its thing it didn't blow, which either means that the lighter uses less than 5 amps, or the fuse is not working as designed.

Interesting as the orignal fuse for that circuit is 15 amp.

J.

That's not 'interesting', that is 'a worry', or even 'dangerous' :shock:

, as I am sure you know.

As most will know, this is how you get electrical fires - the fuse does not blow when an electrical component fails/shorts, the component overheats and .... :cry:

These sound like a good idea poorly executed.

:mrgreen:

Zcootz · Postby **Zcootz** » Fri Feb 03, 2012 4:29 pm

Pop on a few other accessories with the 5 amp fuse in it. Normally the interior light, radio and some other accessories run on the cigarette lighter circuit.

Not sure how much current the lighter on its own would draw but I think the make allowances for higher powered stereos and other things like tyre compressors that you plug into the socket.

Either way 15 amps seems pretty high, but if that's what Mazda specifies.....

aka_juffa · Postby **aka_juffa** » Sat Feb 04, 2012 9:19 pm

I realised today that I had tried to short the wrong circuit. I ended up managing to blow the fuse for the power windows by putting in a 15 amp fuse.

I am disappointed to report that the so called 'glow when blow' fuses did no such thing. I managed to get two of them to blow, but at no time did they glow.

So my suggestion is stick with the regular fuses......cheaper and easier to get.

J.

Zcootz · Postby **Zcootz** » Sat Feb 04, 2012 9:58 pm

If you've still got the blown fuses put one back in, if it doesn't glow turn it around and put it in the other way and see if it glows. LEDs are polarity sensitive, it seems kinda dumb if they haven't allowed for this on their design. Bit of a shame that

taminga16 · Postby **taminga16** » Sun Feb 05, 2012 8:50 am

Zcootz wrote:If you've still got the blown fuses put one back in, if it doesn't glow turn it around and put it in the other way and see if it glows. LEDs are polarity sensitive, it seems kinda dumb if they haven't allowed for this on their design. Bit of a shame that

Jaycar's range of LED globe replacements are, sadly not marked so either and whilst purchasing and hand full the other day the staff member that assisted me had no clue of same (he does now), great products and quite inexpensive in comparison to SCA etc.
Greg.