jeromio Posted May 13, 2003 Share Posted May 13, 2003 So, I've rewired my entire car using a nice 20 circuit fuse box from 2nd gen Maxima. I have the "lights" on one circuit. I put that in quotes because what that really means is that the lightswitch gets power from that circuit and the switch then controls the gauge lights and 2 relays. I have it set up so that the low beam relay stays on when the high beam relay turns on - tryna goose those sucky lights up as much as possible. The relays are 50amp units controlled by 14 guage wires running to them from the switch, and they are grounded about 3 inches from where they're mounted. The juice for the headlights comes from thick 10 guage wires that are both fused off of a common 30amp fuse that is directly connected to the "main" pole. Anyway, I tested all this out before taping it all up - except that I didn't have my gauges at that time. Then, last night was my first time actually driving the car at night. So, lights worked fine, but when I went to flip on my brights, fuse blew!?! It was a 15amp fuse. I put a 30amp fuse in its place for now. But I am confused. Why would 2 relays and 5 little bulbs draw so much juice? I suppose for a start, I should separate the high lows (so that lows turn off when highs are on). I will also go make sure that the connections to the relays are all tight. But is there anything else inherently wrong with my setup? Quote Link to comment Share on other sites More sharing options...
Guest greimann Posted May 14, 2003 Share Posted May 14, 2003 There is nothing wrong other than the fuse choice. If you have two standard 7 inch round headlamps rated at 35 watts low beam and 65 watts high beam (100 watts total each) and both circuits are burning, then the total draw is 200 watts. Using the electrical formula P=IV, where P = power in watts I = Amperage V = Voltage Solving for amps: 200 watts / 12volts = 16.6 amps A 20 amp fuse is not unreasonable and a 15 amp fuse is obviously too small. Quote Link to comment Share on other sites More sharing options...
Tim240z Posted May 14, 2003 Share Posted May 14, 2003 If all that is running through that fuse it the little dash lights and the 'tickler' juice for the relay, 15 amp should be more than enough. Relays need very little amperage, so maybe something else is going wrong. Retrace your wiring. Tim Quote Link to comment Share on other sites More sharing options...
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