The infamous brown wire fix

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jseabolt
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The infamous brown wire fix

Post by jseabolt » Wed May 16, 2018 1:09 pm

As to why I have not done this by now I have no idea. But I am going to do this , this weekend.

So I pulled up the article written by Ken Dixon on this mater. it seems easier than I expected.

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

As far as I know my Spider has the original ignition switch. I bought it when the car was 12 years old and I've owned this car for over 25 years so I know I've never replaced the ignition switch. I did replace the connectors at the white gang connector because they had melted.

So based on that all I need to do is run an extra wire to the unused #30 pin on the back of the ignition switch? So this switch should have an unused #30 pin if it's the original switch.

About 20 years ago I replaced just about every bad ground connector on the car. Then I added one of those lawnmower starter solenoids (From Maduko if anyone remembers them) between the ignition switch and solenoid to fix the "click" I would hear when I'd try to start the engine.

Then I added headlight relays. A couple of years ago I added a 15 volt step up converter for the wiper motor. This helped speed up the wiper motor tremendously.

However there is an issue. Whenever you use a step up converter, the amount of amps the converter pulls is related to whatever voltage you are feeding into it. So the closer you get to the converters output, the less current it pulls. Of course you have to figure in how many amps the device your powering pulls as well. Technically if you feed more voltage to a motor in theory it should pull less amps.

After I installed this step up converter I noticed a problem. Whenever the engine was not running and I was testing the wiper motor, I noticed after a few swipes the 7 amp fuse would blow. The converter is rated for about 10 amps but the wiper motor shouldn't pull anywhere near that. Plus the heater fan is wired on the same circuit with an 8 amp fuse. But with the engine running this did not happen.

My idea was not to actually feed 15 volts directly to the motor but rather compensate for all the voltage drop between all the switches. So by the time power get's to the motor, it's probably closer to 14 volts instead of 11 volts without the converter.

This amperage draw should be linear but for some reason on this converter it seems to spike.

I discovered that when feeding the converter there is a huge amperage draw between 11.? volts (engine not running) and 12.? volts (engine running). From what I remember the jump in amps is like 15 when not running and as low as 3 or 5 amps when the engine is running.

As long as the engine is running, the fuse would not blow.

I ended up replacing the fuse with a 10 amp circuit breaker just in case. I later discovered that sometimes with the heater fan on, the circuit breaker would trip. Now I'm discovering that sometimes the breaker will trip if the headlights are on or the air conditioner is running.

So even though I solved one problem, I still have an issue where I'm just not getting enough power to the ignition switch.

So I think fixing the voltage drop going to the ignition switch would help this.
spider2081
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Re: The infamous brown wire fix

Post by spider2081 » Thu May 17, 2018 12:58 pm

Just some thoughts.
The brown wire that feeds the ignition switch does not run directly from the starters solenoid battery terminal to the ignition switch. It passes through a connector in the engine compartment on the drivers side fender well and also a connector behind the dash before reaching the ignition switch. Either of these connectors could be issues, especially the one in the engine compartment.
The brown wire fix bypasses these connectors.
When you installed the "start" relay and the "headlight" relay you removed the major causes for the ignition switch to fail. The heavy brown wire feeding the ignition switch should no longer have much current flow through it. The headlights and the starter solenoid were the greatest loads. Using the spare #30 contact on the ignition switch does not add a switch contact to the operation. Both #30 terminals feed the same internal switch contact. So in essence the "brown wire fix" adds a second wire to the circuit bypassing the 2 connectors in the factory wiring. This increases the current capacity of the wiring between the battery and the ignition switch but you have reduced the current draw through the wire with the relays.
I think your relays are a great approach to solving many of Fiat ignition switch issues.
Had you tried a relay feeding the wipers directly off the alternators output post before you installed the voltage converter?? I have used this approach with satisfactory results. It is pretty easy to do.
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Re: The infamous brown wire fix

Post by rridge » Thu May 17, 2018 4:15 pm

So in essence the "brown wire fix" adds a second wire to the circuit bypassing the 2 connectors in the factory wiring. This increases the current capacity of the wiring between the battery and the ignition switch
I think Dave has provided the clearest explanation of the brown wire fix for Spider 2000's. I've had to clean those connectors multiple times to eliminate hot no-cranking start situations. I may try the wiper relay suggestion also.
Richard
'81 Turbo Spider
Rockville, MD
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Re: The infamous brown wire fix

Post by jseabolt » Thu May 17, 2018 4:50 pm

spider2081 wrote:
Thu May 17, 2018 12:58 pm

Had you tried a relay feeding the wipers directly off the alternators output post before you installed the voltage converter?? I have used this approach with satisfactory results. It is pretty easy to do.
I actually tried this on a Fiat 131 but I did not see any major improvement as the 12 to 15 volt step up converter.

I also installed a Bosch wiper motor on the 131 like I did on my Spider which works better. The Bosch wiper motors used on VW Golfs and Audis are a small step above the Marelli motors.

For a few years I bypassed the main fuse box for the wipers. I ran a wire directly from the ignition switch through an in-line fuse directly to wiper switch. And this helped. When the wire was connected to the fusebox, it shares the same connector as the heater fan so whenever the heater fan was on, the wipers would slow down even more!

I still have no idea why the charge indicator light glows dim on this car when I start turning on circuits like the headlights, wiper motor and heater fan. The light should indicate that the electrical system is pulling more power than the alternator can produce. But for some reason I've never had a flat battery because of it. Just something that has annoyed me for 25+ years.
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Re: The infamous brown wire fix

Post by rridge » Thu May 17, 2018 5:10 pm

I still have no idea why the charge indicator light glows dim on this car when I start turning on circuits like the headlights, wiper motor and heater
I've had the same dimming glowing charge indicator from time to time. I think it glows because of a voltage drop in the ignition switch wiring but I've never worked out the circuit logic. It has always cleared up when I've cleaned the brown wire connector. As you say it has never resulted in a discharged battery. I think the problem is unique to late Spiders.
Richard
'81 Turbo Spider
Rockville, MD
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Re: The infamous brown wire fix

Post by jseabolt » Thu May 24, 2018 7:13 pm

Seems like it takes me forever to get stuff done anymore. So I finally got around to doing this infamous brown wire fix. I ended up just running the wire to the back of the alternator. Seems easier than the starter. The whole system is connected together anyway. I ended up using a thick brown wire from a Yugo wiring harness. It seems to be around 10 AWG or the same as on the Spider.

So I took some before and after measurements off the circuit breaker for my wipers. Since this circuit seems to suffer the most. The circuit comes directly off the fuse box.

I did not check the battery voltage but it's a brand new battery so I assume it was around 12.6 volts. The other battery went flat on me over the winter and for some reason could not be recharged. Even though I had it connected to a trickle charger. The same trickle charger I had hooked to my Subaru last year and it went flat as well over about 3 months. Like it's actually sucking the juice out of the battery instead of keeping it charged up.

Before the "Brown wire fix":

14.07 volts (engine running)
12.30 volts (engine not running)

After :

14.40 volts (engine running)
12.30 volts (engine not running)

There was no change in voltage with the engine not running before or after (as I would expect) but almost .3 a volt increase when the engine is running. That may not be a significant amount but every little bit helps. You would be surprised how much of a .5 to 1 voltage drop will effect circuits.

The biggest thing is I can flip on every circuit on the car and the circuit breaker going to my step up converter will no longer trip. So yes I would say this was worth doing. But for some reason temperature has some effect. I'm guessing because the blades and the linkage (more resistance when cold) is causing more drag on the motor.

I shot a video showing the wipers in action. Also note how the voltmeter guage drops as I turn circuits on. But otherwise no problems with the electrical system.

https://youtu.be/gRR5HO2H8_c
Last edited by jseabolt on Thu May 24, 2018 7:38 pm, edited 1 time in total.
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Re: The infamous brown wire fix

Post by jseabolt » Thu May 24, 2018 7:15 pm

rridge wrote:
Thu May 17, 2018 5:10 pm
I still have no idea why the charge indicator light glows dim on this car when I start turning on circuits like the headlights, wiper motor and heater
I've had the same dimming glowing charge indicator from time to time. I think it glows because of a voltage drop in the ignition switch wiring but I've never worked out the circuit logic. It has always cleared up when I've cleaned the brown wire connector. As you say it has never resulted in a discharged battery. I think the problem is unique to late Spiders.
It may have been on account of light pollution in my garage but after the brown wire fix, I am no longer seeing the battery indicator light glowing when I flip on all of these circuits.

I'll check in the dark one day.
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