Bought a 21 circuit prewired universal harness. I've been pulling the wires. I don't know where the "Alternator Exciter" (#70 and it's GM brown) wire goes. I'm planning on running a 60 amp one wire alt. On the 1 wire alt. doesn't it only have one wire and it goes to the battery or someplace? Am I missing something?
The normal 3 wire alternator has a power wire from the idiot light, this is the brown wire you discovered. You can remove it if you use a 1 wire alt. Just connect the screw terminal on the alt to the battery, like you planned.
Squirrels got it right, but I might add just to save you some worries later. If you fire the beast up for the first time and don't see any charge, rev your motor up to about 2000RPM and it should kick in. Thats what the old exciter wire did.
So if your running a 1 wire alt. the exciter wire is not used. I read somewhere that the alt wire is connected to the Solenoid is that just as good as connecting to the battery ifself.
6 of 1 or half a dozen of the other. My battery is in the back so the solonoid is the shortest run, but some guys run to the battery that is up top and easy to get at. Yoyr best bet is to choose one and let that be your style from now until eternity.
With the standard old GM internally regulated alternator, the bigger wire that attatches to the rear of the alt with a ringlet and a nut carries the current back to the battery...I usually route it to the stud on the starter where the battery cable is connected, but it can be run back to the battery post directly, too. The small white wire on the two-wire plug is for the "charge" or "alt" light on the dash. The red wire next to it on the plug is the exciter wire. This should be run to keyed-on power. GM and I both favor hooking it to the key switch so that it is powered up when the key is in the 'on' position. However, it can be hooked anywhere that it will receive a 12v supply when the car is running. Lots of people simply loop it back to the stud on the rear of the alternator and call it good, but I was told by a rebuilder that such a practice can shorten diode life within the alternator, and he called it a "hillbilly shortcut". I've seen it done on many rides, and the owners claimed no problems...but I elected to wire it the way GM intended...just to be safe. Either way works, though.
I think that red wire that connects to the plug in terminal is actually a voltage reference for the internal voltage regulator. I also recall seeing it looped to the screw terminal on a stock Buick. I've run them looped back for years and years, no problems. If you chase the wiring on a stock 70s Chevy you'll find that it actually goes thru a fusible link to the battery connection on the solenoid. Just for grins, here's a scan from a gennie GM shop manual for 1976 Chevy full size car. It's looped back.
[ Just for grins, here's a scan from a gennie GM shop manual for 1976 Chevy full size car. It's looped back.[/QUOTE] I've seen a number of GM cars with the loop back done right on the alternator. On the exciter, if you have the exciter wire, and you haven't yet purchased the one wire, why not go with the regular alternator? It starts charging immediately, is cheaper, can be replaced or serviced anywhere on the planet, and I believe it puts out more juice than the one wire too. The one wire is a make-do to avoid the horrible difficulty of running two wires instead of one (!), and you already have the wire there!
I've seen a number of GM cars with the loop back done right on the alternator. On the exciter, if you have the exciter wire, and you haven't yet purchased the one wire, why not go with the regular alternator? It starts charging immediately, is cheaper, can be replaced or serviced anywhere on the planet, and I believe it puts out more juice than the one wire too. The one wire is a make-do to avoid the horrible difficulty of running two wires instead of one (!), and you already have the wire there![/QUOTE] My kit calls for a one wire alt. I ***ume you could run a regular alt, but unfortunalty I have seen wires melt before me, and it was a horrible sight. Not to mention a mess to replace. I don't want to F anything up. So I'm counting on you guys to lend advise, and steer me in the right direction!!
So....The kit calls for a One wire alternator....and has an 'Alternator' wire. Maybe it's for the idiot light? Is the brown wire about 18 gage? What do you do with an idiot light when you have a one wire Alt? Isn't the loop back with the exciter essentially a one wire hook-up?
The idiot light circuit is the exciter circuit, and the resistance of the bulb has a function in blocking it as a feedback preventing the car from turning off! It's the only wire you would need to add for a multiple wire 1970's-80's GM alt, as the third wire is the one you can just run straight from its terminal to the battery hookup terminal right on the alternator. If that wire is already there, I see no excuse for a one wire alternator!
If the car doesn't have an idiot light in the dash, then the 1 wire alternator makes for a simpler installation. But if it has the light, then the 3 wire is the way to go. I run stock gages in my 55, just the idiot light to tell me what the charging system is doing, and it all works so well that I don't even think about it. I just replace the battery every 4 years, and life is good.
ya it's a thinner wire. It's in with the engine bundle. So i guessed it goes up there someplace. I am thinking the kit is covering all the bases. It called for a 1 wire, but give instructions also for the other alts. I'm just wanting and hoping this is going to be an easy project. The more I think the more I get scared I'm going to screw it up. I hate when I start fiddlin'!
The Jalopy Journal
