Electrical question....

[SilverY2KCivic]

After looking at some site on general how-to's on some mods you can do to your car as posed on the "Technical" section of www.jdmfan.com I was wondering, if I tap extra things into existing circuts on my car, do I run the risk of shorting anything out, or blowing and fuses? Let me explain what I'm questioning about....

For one, I just installed some aftermarket fog lights (PIAA style, but not the real PIAA though) onto my car last weekend, and for the power signal line to the relay for the fogs, (the wire that gets the [power signal that tells the fogs when to enguage or not), I ran that wire to my parking lights into a wire harness that is under my dash, and hoses the wires for mich of the lighting of my car, such as parking lights, and dash lighting. By tapping the wire from my fogs into that circuit, should I upgrade my parking light fuse, or have to worry about too much of a power load pull off there? I also have a pair of screw LEDs that I have holding my rear license plate on, with, and those are tapped into my parking lights at the harness to my tail lights. And I also have my Auto Meter tach wire tapped into my dash lights (which centrally goes to the parking light curcuit). Am I drawing too much of a load to this curcuit, or am I just fretting over nothing? Also, I have my amp remote wire currently tapped into my 12+ ignition wire under my dash (the thick black with yellow stripe one to the fuse box), would I be drawing too much power with that? I want to very soon switch that wire of to the power wire to my stock radio, so it'll turn on with hthat rather than my ignition, would I need a fuse to that wire when I route it to the radio power wire? When do I know if I need a bigger fuse, or a fuse period to anything electrical I add to my car?

[crxlvr]

well first off remove the remote wire from your ignition, thats just a problem waiting to happen, you should never tap anything into your ignition wire other then alarm functions. Secondly the fuses in your dash should remain the same amperage, the fog lights should have their own in-line fuse that will blow if the current it too high, with the rear screw lights they draw about 0.02amps of power to light so there is no problem there, as for the tach, id suggest to put in a slightly higher fuse, one up from the current one just to be safe, but its never recommended to switch a fuse with a higher one.

[SilverY2KCivic]

Originally posted by crxlvr
well first off remove the remote wire from your ignition, thats just a problem waiting to happen, you should never tap anything into your ignition wire other then alarm functions. Secondly the fuses in your dash should remain the same amperage, the fog lights should have their own in-line fuse that will blow if the current it too high, with the rear screw lights they draw about 0.02amps of power to light so there is no problem there, as for the tach, id suggest to put in a slightly higher fuse, one up from the current one just to be safe, but its never recommended to switch a fuse with a higher one.

Thanks for the heads up with that. The amp remote wire I'm planning on relocating it today anyways, since I found out what color the radio power wire is, so I'll just tap it into that. I also forgot to mention that I have my tach +12v power wire hooked to my ignition wire as well, but I'm gonna relocate that to a blank terminal on my fuse box under the dash, the turns on when the ignition is enguaged, so that shouldn't be a problem either. As for my fogs, they DO have their own inline fuse to them, but I was thinking of the parking light curcuit in my car as a whole, with tapping the power signal wire from my fogs, in that circuit.

Again, thanks for the help.

[fritz_269]

The easy answer is:
If you ain't blowing anything, you ain't got a problem.

Always carry a few extra fuses just in case though...

LED's take around 0.04 A each, so they're not an issue until you get 50 of them. The tach probably draws about 0.1 - 0.5 A or so, but again, as long as you're not blowing a fuse, everything is just fine. I also hightly doubt the amp's remote turn-on wire would pull any more than 0.1 A.

Automotive relay coils run between 50 and 100 ohms, meaning that they will draw between (14V / 50Ohms =) 0.28 Amps and (14V / 100Ohms =) 0.14 Amps. Not a problem here either.

I think the main issue you've heard about is when (not so smart) people tap their fog lights directly into their parking light circuit, without using a relay. A pair of 55W fogs will draw about 110W/14V = 7.9 Amps. Quite likely overheating the parking lamp circuit and hopefully just blowing a fuse before anything melts.

[SilverY2KCivic]

Originally posted by fritz_269
The easy answer is:
If you ain't blowing anything, you ain't got a problem.

Always carry a few extra fuses just in case though...

LED's take around 0.04 A each, so they're not an issue until you get 50 of them. The tach probably draws about 0.1 - 0.5 A or so, but again, as long as you're not blowing a fuse, everything is just fine. I also hightly doubt the amp's remote turn-on wire would pull any more than 0.1 A.

Automotive relay coils run between 50 and 100 ohms, meaning that they will draw between (14V / 50Ohms =) 0.28 Amps and (14V / 100Ohms =) 0.14 Amps. Not a problem here either.

I think the main issue you've heard about is when (not so smart) people tap their fog lights directly into their parking light circuit, without using a relay. A pair of 55W fogs will draw about 110W/14V = 7.9 Amps. Quite likely overheating the parking lamp circuit and hopefully just blowing a fuse before anything melts.

Hmm, interesting. Well with the fog lights that's EXACTLY what I did, I took the power signal wire (the main power wire obviously goes directly to the battery with a 20a fuse in-line between the batter and the relay for the fogs), I had the power signal wire (which tells the lights when they can an can't come on when the ON/OFF switch is in the ON position), I had it tapped into the wire harness that the interior instrumentation lights feed to, and I switched it from there, and tapped it into the main wire that feeds power to the parking light curcuit. The instructions for the lights say to tap into the parking light curcuit, so I'm assuming it's fine as I now have it, I haven't yet blown any fuses, and haven't melted anything that I know of yet, and I assume that if I haven't doen either of those yet, I won't at all. If a fuse is gonna trip, it'll do it right off the bat, am I correct?

For the other wires I was asking about, I hooked the tach's +12v power wire to a blank terminal that engauges when the ignition is turned on, for an unused accessory at the top io the under dash fuse box, and the amp wire, I hooked to a blank terminal also at the top of the fuse box, that engauges when the key is in the "ACC" position, and I put a sliding type switch between the wire and there it's hooked to, so I can turn it on and off at will, when it's getting power to it. I'm thinking I should be fine the way I have all the mentioned hooked up, if you all see any errors in how I have described my wiring, PLEASE do let me know, thanks.

Fritz, if it'll help any, I can stop by sometime this weekend and you can looksy it over for me just to be sure.