Time for brown wire surgery???

[kristoj]

Guys,

My wife and I drove the Spider about an hour north last weekend for a micro-FLU event with two other couples. We had a wonderful day, including an extended visit to a local Alfa/Fiat repair shop and an awesome dinner that night (thanks to Bob Tyrell And his wonderful wife Jean for hosting us at their home for dinner).

Anyway, on the drive home, we had the heater and headlights on at the same time. Believe it or not, I have never driven at night with the heater on before. This caused the alternator light to begin glowing dimly. As soon as I switched off the blower motor, the light went out. I turned the blower back on, the light began glowing again. So we drove home with the blower off. At speed, plenty of heat gets inside.

Any suggestions as to what this means or how to correct?

[So Cal Mark]

sounds like low output from the alternator. Check the tension of the belt, then test amp output of the alt. A bad diode in the alternator will cut output by 1/3 but still charge

[Blast]

You probably know to do this, but sometimes I go looking at all the tough things, overlooking the simple and obvious. Be sure to check alternator belt, alternator connections, battery connections and for corrosion. The blower fan motor itself could be pulling a lot of current if the bearings and other parts are old and gooped up. I hope its the simple, but at least it gave you a warning.
Blast

[Blast]

As a matter of fact, in the new dash I'm building, I'm losing the clock, and putting in a voltmeter.

[rlux4]

John, I haven't got it completly figured out yet, but so far I'm thinking our FI cars don't really need the brown wire surgery. We have the one 10ga. brown wire coming up to the ignition switch from the battery post (direct feed from the battery) and the other 10ga. brown wire going from the battery to the dual relay. I'm not great at interpreting wiring schematics, so it's slow going, but so far brown wire surgery in our case doesn't seem to be beneficial, only redundant.
If I'm wrong, I stand to be corrected. (Would save me a bunch of studying.)
Ron

[kristoj]

I'll have to take a look at the alternator. I had it all completely apart earlier this year, so could be a loose connection. I keep it on a battery tender when I'm not driving it, so I would really know if it is fully charging unless I check for amps

[mdrburchette]

I'm wondering the same about my early model cars. The brown wire on mine goes from the ignition switch to the starter and shares the same stud as the black wire that goes from the starter to the battery.

[ga.spyder]

Ron and John,
from what I have read and seen on other posts,the extra brown wire doesnt really benefit our cars.Maybe Mike B. will chime in on this,he is the brown wire guru. I did add the extra wire on my 82,I really didnt notice any change..positive or negative.My batt. light also glows dimly at night w/ heater and radio on and has since I bought it.
Craig

[rlux4]

That does tend to confirm my suspicions Craig. What led me to suspect it at first was the fact that the connector behind the ignition switch was in cherry shape after 25-26 years. No brittleness or discoloration which overheating would have caused.
Ron

[mdrburchette]

Why can't you just check how much voltage is at brown wire connector of the ignition switch. I would think if it reads the same as your battery, you're good to go.
As for the way mine's set up, I don't see any benefit to the brown wire surgery.

[mbouse]

Like Ron, i tend to be pretty dang hands on...see it, believe it. Read the schematic? I get lost. I've not dabbled with fuel injected vehicles and their different wiring. Is there a 10 ga or larger wire that runs directly (without splices or connections) from a power source to the ignition switch on these cars?

I have added head light relays to F.I. vehicles and heard words of praise from their owners.

BWS was "invented" to fix issues at the consumers of power..the lights and motors. BWS assumes a fully functioning charging system, battery and alternator. Because of interruptions and degradation in the factory wiring, the ignition switch was not seeing a full 12+ volts, and therefore could not distribute what it did not have. Vehicles that typically gain advantage of BWS see only 9-10 volts at the equipment. I personally saw 9.5 and 10.3 volts at my motors before i added the extra wire to the ignition switch. BWS does not alter the charging systems ability to produce voltage, it merely better distributes the available power to the ignition switch.

AFTER i performed BWS on my carbed '80, i also added headlight relays to my lighting circuit because i was still getting under 11 volts at the bulb terminals after BWS. Seems the headlight switches can actually catch fire if they are allowed to degrade enough. Mine did not get that bad, but those switches were sucking down a heck of a lotta juice, and not passing it on.

John, you did not say that the blower motor turned slower than normal. you also did not say that you visibly saw a decreased headlight beam while the blower motor was on, verses the beam while the blower was off. True that your consumption is affecting the charging system as the power is feeding the equipment rather than the battery. Doesn't take much time to set a volt meter at the headlights and perform a simple reading with the blower on and off. if you see no change, i doubt that BWS would fix anything.

Certainly adding another 10 ga wire to the ignition switch directly from the starter, battery or alternator is not going to hurt, John. But, i would be more inclined to believe that "idiot" light and suspect the charging system.

I defer to Dr. Dave, who lives in the electron world.

[majicwrench]

Charge lights work on a pretty simple principle, when the voltage is the same on both sides of the bulb the light goes out. When the voltage is different on either side, the light comes on. Under heavy electical load, it takes a car with a dang nice electrical system to have the same voltage at every point in the system, and if the voltage on one side of bulb is even a half-volt different than the other, the light will glow. I would first start car and turn all electrical stuff off, check running voltage revved up to about 2000rpm, should be 14.5 volts or thereabouts. Now turn everything on, and check again, again at 2000rpm, will be lower this time, give it a minute to stabilize, but should still be above 13volts. If it is staying well above 13volts, the system is working, but still would be nice to get light to quite glowing. If voltage drops below 13volts with engine running and at 2000rpm, you have a charging system problem that needs to be fixed.
I have a vehicle that the charge light glows with everything on. Need to fix it someday, has been doing it for 15years now.
Keih