todda1 Posted May 6, 2006 Share Posted May 6, 2006 Hey folks, I'm in the midst of putting a Cadillac alternator on my 92 Loyale (with a/c) and have a question regarding the molded plug in the rear of the Subaru's alternator. It appears the smaller white/ red wire goes to the dash warning light, but I'm confused about the purpose of the larger black/ white wire. The wiring diagram I have, shows it it receiving power from the battery; it's got a fusible link inline. It's purpose is powering the fuel pump relay and the ignition coil. I put a meter to the wire in question, and it's definitely hot. If it's receiving power directly from the battery, do I need to hook it up to the Caddy alternator? Just for my understanding, if the wire's already hot, why is it hooked up to the alternator at all? Thanks, Todd Quote Link to comment Share on other sites More sharing options...
todda1 Posted May 8, 2006 Author Share Posted May 8, 2006 anyone? Quote Link to comment Share on other sites More sharing options...
bgd73 Posted May 8, 2006 Share Posted May 8, 2006 I would no doubt get it wired up the same as now. The purpose for caddy alternator is larger amp? I would be doubting a flawless install and run.A new subaru alternator is cheap (reman). Is there a prob now with lack of 12v amperage? If so, check system grounds.Straining resistors for a bit more amperage is risky.I had my car with "half" of an almost burnt fusible link near the coolant bottle (Perfectly not quite broken!) I had dim lights, bad radio and on and on and on... Good luck with project, do you have means to take pics? Quote Link to comment Share on other sites More sharing options...
todda1 Posted May 8, 2006 Author Share Posted May 8, 2006 The purpose of the swap is more amperage. The stock 65 amper can't keep up with the stereo when the lights, wipers, etc are needed. I've watched the voltmeter drop well below 12v when the bass is hitting, and I've actually had my car shut off as a result. I believe the alternator that I pulled is good for 105 amps. There wasn't really anything involved so far other than building a tray to relocate the battery to the spare tire's area (due to the physical size of the new alternator) and simple mock up. The alternator needed to be clearanced to fit the mounting tab (as seen in other threads) and an extension arm for the adjustment arm was made from a leftover part from a garage door opener. I've verified the hood closed with the battery in the new home and the Caddy alternator installed.... I was't sure it would! I just need to get some longer belts, and some new 4 gauge cabling. I post some pics, when I get back to work on it. -Todd Quote Link to comment Share on other sites More sharing options...
fastenova Posted May 8, 2006 Share Posted May 8, 2006 I am not sure if it's the same setup or not, but... In my ea81, the alternator has an internal voltage regulator. That line is a 12v from the battery, as you mentioned, and is called the 'exciter wire'. Basically it tells the alternator what voltage it needs to produce. Check out this article for more info: http://en.wikipedia.org/wiki/Alternator Definitely hook that line up. Quote Link to comment Share on other sites More sharing options...
Cougar Posted May 8, 2006 Share Posted May 8, 2006 If the B/W wire you mention is not the main output wire then it is the "sense wire" for the alternator's regulator. As voltage on the line from the battery goes lower due to load on the electrical system the regulator then makes changes to the alternator output to compensate for the added load. The W/R wire is for the warning light as you stated and supplies voltage for the exciter also. If the waring light burns out then there will not be any output from the alternator. I first learned of this many years ago trying to see why a alternator wouldn't work. I finally found the bad bulb and changed it. Quote Link to comment Share on other sites More sharing options...
todda1 Posted May 8, 2006 Author Share Posted May 8, 2006 Ok, correct me if I'm wrong, but it seems as if I'll connect: The single output post (on the new alternator) will go directly to the battery with new 4 gauge wire; a fusible link will be inline. The mystery white/ black wire will also be jumped to this post.... that's the only place to put it on the caddy alternator. The small white/ red will go to the dash. I linked to another thread that shows the rear of a GM alternator. It looks to be what I have. I'll just be running pigtails and male spades to jump into the Subaru's harness. http://www.ultimatesubaru.org/forum/showthread.php?t=15457 Hopefully, I'll get to finish it next weekend. Thanks all, Todd Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted May 8, 2006 Share Posted May 8, 2006 If the B/W wire you mention is not the main output wire then it is the "sense wire" for the alternator's regulator. ... . Be Carefull with this Wire, or you`ll not get brighter lights and batery will discharge faster. Quote Link to comment Share on other sites More sharing options...
todda1 Posted May 8, 2006 Author Share Posted May 8, 2006 What do you suggest I do with this wire? Are you suggesting that this wire will cause a drain, if hooked to the battery? -Todd Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted May 8, 2006 Share Posted May 8, 2006 No. I suggest to be Sure where to Attach it, before you connect it, because of This: The Stock Alternator (Hitachi) -as the Cadi one- got an Integrated Circuit (IC) that regulates how much volts/Amperes (Power) out will deliver the unit, in order to fulfill the requirements of the Car´s Electric System demands, for example: with all lights off, just engine running; the power consuption will be less than in night time, with all ligts on; so this cable lets the unit to deliver less or more power to the battery just when it is needed. Why don´t just connect it to the Battery? Because it could Overload your battery & System. How? Well... too much power getting in the battery all the time, will "Fry" the Battery´s Cells, makin´ your battery to last shorter -maybe Very Shorter- Also, power overload increases in Volts, not just in amperes; so it can "Burn" your Stereo, Headlights or Halogen Bulbs; etc... So, that is why I told ya, to check and be Sure before to connect any Cable, Specially this; or you´ll get one of this two results: System OverLoad, or Poor Power Out... Good Luck! Quote Link to comment Share on other sites More sharing options...
Cougar Posted May 9, 2006 Share Posted May 9, 2006 You may be able to just tape the end of the wire and store it. Attach the other two leads as you stated and leave the B/W taped by itself. Start the car and turn some of the lights and blower on. Check the battery voltage to make sure that the battery voltage is around 13.5 volts when you rev the engine to around 2k RPM. If the battery stays charging then you don't need that wire tied to the alternator. Since it ties to the battery though it must be isolated from ground and any other things so tape it well. Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted May 9, 2006 Share Posted May 9, 2006 Yes, but I forgot to Say this: That wire is the "Actuator", I mean is the one that indicates the alternator to switch from half power to full power, like in the past example, with lights off or on, so it was connected to the Hitachi alternator, and now I think is nessesary to connect it to the new unit. Maybe you still got around 13.5 Volts with all electrical stuff on, but if the "Actuator" doesn`t switch the alternator to full power, those 13.5 volts will be with just around half amperes the unit can do. I suggest to search about the new alternator diagram to connect the wires in correct way. I think your new alternator is still with Integrated Circuit built in, like the Hitachi stock one; unless it is from a model of 1979 or older... Those ones got an "External Relay" that regulates how much power the unit brings to the vehicle`s system. (It`s a "Black Box", ussually of 4" x 2") My old Mercury Comet Caliente 1969 got this "External" Regulating Device design, that is why you can see a much brighter light comin` from old american cars under acceleration; Integrated Circuit built in the new Alternators, maintain almost always 13.5 volts, just changes the amount of Amperes to the System, unlike the old "Black Box" that changed both Volts & Amperes. I wish this could help you... Good Luck! Quote Link to comment Share on other sites More sharing options...
Loyale 2.7 Turbo Posted May 10, 2006 Share Posted May 10, 2006 Also I forgot to Say this: with the "Actuator" Cable wrong connected, your alternator will bring just one of this two posibilities: High Power Always, or Low Power Always. High power Always can be good just for drivin` almost always with lights and/or AC on... or your battery will overload. Low Power Always can be good just for "Daylight" drivin`... or with lights and / or AC Off... or your battery will discharge fast... *** *** * *** *** I wanna tell ya, that the Integrated Circuit (IC) of my EA82 (That switches between power outputs, you know... ) have failed just two days before I did a trip (About one Month ago) to Managua - Nicaragua (About 1,100 Kilometers) and my battery is only three months old... AC-DELCO. It did "Stuck" in High Power Always... Even with Lights and AC on, the needle on the Dashboard indicates Around 16 Volts... ...I did ran my subie like this since the day that failed because I don`t have enough money to buy a new IC for the Alternator... and bad IC means blown solenoid Resistors (Small silver-rounded devices that control voltage stability... excuse my bad english... My mother tongue is spanish) I was waitin` `till end of may, due to that is my pay day... but my battery awaked "Fried" today... Too Late... TODAY my battery awake damaged... the cells near the positive terminal, are short-circuitin`... I can see "Bubbles" with the car on (Chargin`) so now, I`ll push downhill my subie to start it, untill the end of may... So, be careful with that underpower / overpower situation... I suggest to first install the new alternator and then, with a tester (And the Dashboard voltage indicator) you can be certain if your unit switches good from low to high power under lights on / off situation... Good Luck! Quote Link to comment Share on other sites More sharing options...
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