Headlight Fuse is Melting, not breaking but MELTING!

[Motorbreath]

ok

i thought that a bad wire would cause an increase in load in the same as say heated grips cause an increase in load.

Yes, the heated grips are in parallel, so they decrease the resistance of the complete circuit. (current runs both thorugh the original circuit and the new grips circuit)

As some one said earlier in the thread heating is due to increased resistance or load if the bulbs are standard and in good order I would suspect a poor conection - Its a simple enough circuit so I would check and clean the conections and put in a new fuse.

You can never rule out the PO factor ( previous owner) - my wiring was getting real hot when on full beam - on inspection the main beam on one bulb had a wire soldered on it linking it to the un used dipped fillament - way too much load - again strangly didnt pop a fuse but the bulb connectors started to melt!

As said before, resistance reduces heat. As you describe it probably you had both H4 filaments enlightened, that caused the excess of heat. Your fuse couldn't break because there wasn't more current thorugh the circuit, actually there was a bit less. The normal headlight mod we all do increases current as both bulbs are in parallel (but just one H4 filament), but still it is not enough to melt the fuse or anything else.

Again that strange word "load". I do not understand what you mean, but it seems it causes confusion. I do not know even how to translate it to Spanish when talking about electrics.

http://www.aeroelectric.com/Mfgr_Data/Fu..._Specs.pdf

Here you go, all you need is a multimeter set on DC amps in line with the circuit and you see what's happening.

It seem fuses apply the 80% rule. It means a 20A fuse can melt if it has 18A running all the time? But he measured only 10A already, mayby he is wrong.

Hey everyone, thanks for all of your responses, I'll change the bulbs and then do a more thorough check of all the connectors and wires in the circuit.


@unfazed
I do have a modded headlight but the problem still occurs when I disconnect the wire, it even does it when just the side/tail lights are on so I'm not sure it's an issue.
Thanks

What mod? Did you replace the fuse?