Automotive Electrical info and FAQ submissions thread.

[GLwagon]

This is a good place to post on what you should & shouldn't do to automotive electrical systems...

Fuses - They are there for the protection of the car & wires... ALWAYS replace fuses with the exact same size or smaller.
by up-sizing a fuse you have created a potential fire hazard...
If a fuse is burning out it is probibly doing its job.

Automotive batteries are not the same as Deep Cycle Marine Batteries... If you discharge a car battery too deeply you run the risk of damaging cells in the battery & turning it into junk...
Older batteries are more susceptible to damage.
Marine Batteries are NOT designed to start cars...

* Registered users of the site do not see these ads.

[munkis]

you like dem stickies.

lets form a FAQ off this thread first.

then I will merge it with the formulas thread, dont want to clutter it up to much with to many stickies.

an FAQ would be something along the lines of questions and answers, rather than informational paragraphs, the above info would be more along the lines of what should be put in the Basic Electrical Information thread.

an FAQ would consist of just that questions and answers.

Q. I just put in seats with out airbags in my WRX, what size resistor do I need to make the air bag light shut off.
A. 3.3 ohms.

so lets get a list of some common questions, we will find the answers and I will either merge or make a seperate locked thread with all the FAQs, and if you want to add more just put them in this thread and I will update it.

Jay

[cdvma]

http://forums.nasioc.com/forums/show...hreadid=304595

Q: What wires do I need to hook up to a starter button?
A: In the ignition harness (under steering column) you need the black one and the black/yellow. Crossing these two with the key in the "ON" position will crank the starter. Cutting the black/yellow one will disable starting with the key.

[iceweazel]

I'm way too wasted tired, but things I hear a lot and see on the board that could use FAQ entries:


- how do I hook up fogs for full time action on the switch?

- how do I convert my single filament HID kit to work with the
WRX? ( 2 parter if I recall with relays and diodes, and unhooking the correct DRL igniter? or was it relays and diodes and unhooking the fogs to run full time? brain fry.)

-where is a schematic for XXX? (radio, lights, fogs,etc)

-whats the little Denso unit in the WRX trunk? (fuel injec. comp)

etc...


Ed

[ride5000]

it might also be handy to go over some basics.. like:

in a series circuit all elements in the circuit see the same current flow, but they do not necessarily have the same voltage across them.

in a parallel circuit all elements in the circuit see the same voltage across them, but they do not necessarily have the same current flow through them.

a reference to a wire table like the one i have on my website would also probably be a good idea:

http://ken-gilbert.com/techstuff/AWG_WIRE_TABLE.html

-ken

[munkis]

ride5000, do I have your permission to link to your site?

Ill add the info about series and parallel ckts as well.

Thanks!

Jay

[ride5000]

absolutely, link away! i got the info on the web somewhere but i made i look a little better, and my site is stable. i know from my electronics work a wire table is pretty much indispensable.

-ken

[turboICE]

Could you put up the resistor specs for various CEL fixes? How many ohms? Like the rear O2 and the EGT in the uppipe.

[munkis]

i certainly can, if someone can provide me with them

Jay

[GLwagon]

EGT in the uppipe needs to be around a 2.2k ohm, 1/2watt resistor... this will fix a P0546 cel

As far as the dreaded P0420 there are some threads on this somewhere, but I like the
Pony Express MIL eliminator

[turboICE]

I had seen the 2200 ohm, 1/2 watt, elsewhere I just wanted it confirmed and also figured it would be a helpful FAQ for others.

The lowest price I have seen for the P0420 fixes is $12 and the PE one is $21. Some might not mind, but come on I think it is just a resister with heat shrink. So if someone doesn't mind take off the heat shrink and getting the specs off the resister you can help the rest of us out!

Edit: OK so the P0420 "fix" is what appears to be a 1K resistor and a capacitor - it is just a low pass filter.

[cdvma]

Originally posted by iceweazel
- how do I hook up fogs for full time action on the switch?

Yes, please put this one up. It is asked way too many times.

There are three links in this thread
http://forums.nasioc.com/forums/show...hreadid=338072

this one seems to be the most direct path to the answer
http://forums.nasioc.com/forums/show...threadid=37232

[munkis]

thanks guys, updated the sticky with a threads of note section, so any thread you think might be important, most importantly, fog light mod threads, and the like, just post'em in here and I will add them.

if someone can get me a clear cut chart of resistors sizes for the different applications, that would make it easier for me to post.

Jay

[Chewy-WRX]

Hey all,

The Turbo Timer w/ Factory Alarm Issue seems to be a regular topic. This is the thread I put together a while ago with pics. Everyone seems to have had good luck with it.

http://forums.nasioc.com/forums/show...hreadid=301643

-Chewy

[armand1]

Since people are always asking about the 2 DRL-disable methods, here's a good thread that mentions both and has good photos of the preferred behind-the-glovebox method:
Good DRL-disable mod thread

[Louie]

The manual doesn't show a type or specification.

I assume it will be a 12v/55w

but is it an H3 or H7?

Please tell me I can use my Ion Crystals on this car...

[bheinz57]

Louie, H3 for fogs for our impreza's...

[jblaine]

The 2.2k ohm EGT resistor EGT CEL fix has not been added yet to the sticky, FWIW.

I think some sort of official grounding mod Q/A should exist too. I want to know, for instance, if it really will help smooth out oddities in the powerband like people say or if that was just because the ECU got reset during the install, etc. It's such a "vague" mod that I hesitate to "waste" $60 on it. Is there no consensus and long-term testing to assure that things like part-throttle hesitation stays gone, etc?

[steak]

I need to find the ignition line to tap into for my a/f guage where is it?

[Speedwagon]

I think there should be a reference for the question of:

I need to hook up my gauges. Where is a good place to tap into for power and lights?

I've seen this darn question asked quite a bit recently. And the answer is way to simple.. anywhere there is power! It's not like gauges are going to put a strain on a circuit, thier power draw is minimal.

[turboICE]

Except post ^ that in 2.0 litre since that is where it is most frequently asked.

2.2k still needs to be added for EGT.

Also P0420 CEL is a low pass filter - mine came with a 1k resistor and a small capacitor - don't know the size but it had a 1 above a 35 on it. <=silly me for buying a $3 "fix" for $12 that I had to solder together.

[vrg3]

Originally posted by Speedwagon
And the answer is way to simple.. anywhere there is power! It's not like gauges are going to put a strain on a circuit, thier power draw is minimal.

There's a bit more to consider, though. You don't want to tap power off a critical circuit because a short in the gauge could blow a fuse. It would suck for a faulty boost gauge to kill your engine computer instead of just your radio, for example.

I would say a better answer would be to tap off any other accessory -- radio, clock, etc.

Then there's the whole illumination issue, which is more complex.

[Charged Performance]

The OEM performance gauge harness connects off the radio harness anyway so you will be certain that it is on a circuit that is appropriate to the application - enough for the gauges and a circuit that is noncrucial to the vehicle operation.

[GravelRash]

Here's a link to a variation on the AWG wire table ref'd in the FAQ:

http://www.powerstream.com/Wire_Size.htm

This includes a nice little calculator to see what the voltage drop will be for a given size / length / amperage circuit leg. Very handy for selecting wire sizes, e.g. for headlight upgrades, added lighting, etc.

[MK19_]

Heh, how about a link to a site that gives Subaru wiring diagram symbols? I can't seem to figure out some of them...