fog light rewiring
@DarrenGT: yes, my fogs a.k.a daylight driving lights
come on every time my engine is on. it's actually a safety feature i'm mimicking from car brands like volvo, porsche, mercedes, audi etc which have their daylight driving lights activate with the ignition.
what i did was tap the feed from the rear window demister, which runs on a 30A fuse and is activated only by the key on IGN position. if you take off the fog switch from the dash panel, you will noticed that it only has 2 wires:
a) one is energized (when the switch is OFF) and most likely taps from the parking light loom, and
b) the other heads to the lights to energize them when the switch is flicked to ON
all i did was cut off the energized one and fed the new feed from the demister line. i then used the parking lights feed to illuminate my boost gauge..
reason i taped the feed from here is:
1] you
MUST fuse your fogs regardless of what kinda re-wiring you are doing to them, and
2] the fuse must be large enough to take the load when you have both your demister and fogs running
here's a little math behind it;
P = I x V where; P = power (in watts); I = current (in amps); V = volts (in volts)
so, in my case, power consumed by the fogs would be 110 watts (55w x 2 bulbs)
car voltage is constant at 12v
so current flowing through the circuit would be;
I = P/V
I = 110/12
I = ~9.17A (let's round it off to 10A shall we)
so 10A plus whatever the demister is drawing (assumed at around 17A will still leave you with some safe room for normal operation without popping any fuses.
does it all make sense..?