Sorry mate but that's a bit wrong.. the current does not increase.
an increase in resistance at the fusebox terminations of say.. one ohm, would give you a total circuit resistance of two ohms (heater element is about one ohm) therefore the circuit would be dropping only six volts across the element and a further six volts at the fuse box terminations, power dissipated at the fusebox would be
6V x 6amps = 36 watts, hence the melting, power dissipated at rear screen will also be 36 watts when it should be 144 watts, hence the crap de-mister, (12V x 12 amps) at switch on.. steadily reducing as the element resistance increases due to heat.
In other words it is not a 'current/amps' problem.. therefore sticking lower rated fuses in won't help.
I think that if your screen takes more than one minute to de-mist.. (just mist.. not freezing ice) you may be developing a problem... just a guide though
The only way to fix this problem is to fit a relay..just like Red Zeppelin did.
Sorry for being so serious but I dont think we should f*** about on this thread. Fire in a tin box full of fuel aint funny.
Last edited by seadart; 09-12-10 at 18:48.