Brown Wire Fix......Again

[Red76]

Sorry to start this thread again but I'm a bit confused. I plan on also doing the brown wire fix this weekend. I have been pouring over all the old posts on this topic that I can find. That's where the confusion kicks in. I thought I had a pretty good set of instructions.

http://www.mirafiori.com/faq/content/bwfix/bwfix.htm

My only question was going to be does it matter what solenoid post I use?

But now after reading older threads I see the extra wire can be run to the started solenoid, the pos post of the battery or the alternator. The pos post on the battery seems like it would be the easiest, does is make a difference?

Again, sorry to bring this topic up again. Just don't want to fry my system.

[digitech]

All in all, it doesn't matter which you use; you're just trying to find a nice beefy 12v supply and any of those will do. Depending on your particular car, one source may be closer than the others or make for an easier wiring job.

[Red76]

I have a 76, It has the upgraded alt on it so I'm not gonna screw with that. Took a while to get that working right anyway. Just gonna run to the pos on the battery. Will post the results.

[aj81spider]

My opinion - a new Spider owner, so not a Fiat expert, but an electrical engineer, so take this with as much salt as you want. I would run the new wire to exactly the same point the old wire starts. Taking power from a different point will result in a slightly different voltage. That different voltage means more current will be running down one wire than the other, and might result in current flowing in odd pathways. Running the wire to the same place means both wires will start at the same voltage and the currents will be mostly balanced, giving you the most benefit of the fix.

Just something to consider.

[Red76]

My opinion - a new Spider owner, so not a Fiat expert, but an electrical engineer, so take this with as much salt as you want. I would run the new wire to exactly the same point the old wire starts. Taking power from a different point will result in a slightly different voltage. That different voltage means more current will be running down one wire than the other, and might result in current flowing in odd pathways. Running the wire to the same place means both wires will start at the same voltage and the currents will be mostly balanced, giving you the most benefit of the fix.

Just something to consider.

When I think about it you have a point. On that note would you not need to have the exact same length of wire and gauge wire to match the voltage. Not an expert here but you got me thinking.

[aj81spider]

From an electrical point of view, if you want to have half the current flowing through each wire you should match the length and guage. If you get close on either you're probably good enough as the resistance differences will be small enough that the current will largely be balanced. I'd be more concerned about the voltage differences if one were originated at the battery and one at the alternator.

[artmunson]

I recently did this modification with Great results. Thanks again to those who figured this out and were willing to share. I ran my extra wire to the alt because it was easier to get to and if you run the wire along the fender with the other wires than it is about the same distance from the switch as the starter. I must admit I did not follow the advice to a "T"...I used #12 RED wire instead of brown!!! Shame on me!!!
I must say this again. I have been driving my Fiat for years and looking for a bad ground to fix my weak headlights,slow wipers and dull dash lights, I now have a big smile on my face when I drive home from work every night...I CAN SEE!!!! I also have not experienced the "click click" thing I had going on with my starter!!! Thanks again guys!!!

[dantye]

Sorry to start this thread again but I'm a bit confused. I plan on also doing the brown wire fix this weekend. I have been pouring over all the old posts on this topic that I can find. That's where the confusion kicks in. I thought I had a pretty good set of instructions.

http://www.mirafiori.com/faq/content/bwfix/bwfix.htm

My only question was going to be does it matter what solenoid post I use?

But now after reading older threads I see the extra wire can be run to the started solenoid, the pos post of the battery or the alternator. The pos post on the battery seems like it would be the easiest, does is make a difference?

Again, sorry to bring this topic up again. Just don't want to fry my system.

You might want to consider the IAP relay kit. It will cost more, and maybe even take a bit more time, but you will not need to worry about wire gauges, etc.

Good luck, whichever way you go.

Their instructions are not perfect, but they helped by answering questions by phone. You can see my video and notes at: http://youtu.be/p6W6r7_DJyY

[digitech]

For the purpose of this mod, you do not have to worry about slight voltage diff. due to different sources, the idea is to double up the wire gauge and supply 12v from a heavy duty current source instead of running it all through a single contact on the ign. switch.

[artmunson]

What was the original purpose of the extra connector on the ign switch?

[2ndwind]

So do I understand the brown wire fix (BWF) is a substitute for putting relays in for the headlights? Thus greater power than desirable still runs through the ignition switch with the BWF?

[courtenay]

I don't think the BWS is a substitute for a headlight relay. No question it will help, but the relay also takes a big load off the ignition switch and should be done as well.

[digitech]

Absolutely.