alternator wiring problems.

[YZEATER]

ok i give up. please help. sorry really long.

85 chevy/gmc truck 3/4 ton, originally a diesel, now has a built 383 with msd ignition, serpentine belt setup.

all was fine until i started screwing with the gauges. i cut the printed circuit board on the back of the gauges, before i knew you should never do that. i think the cause of the problem was the alternantor needed voltage to it to tell it to start charging.

well now i just want to do away with that if i can and wire it up direct. the alternator i have has a plug with 3 wires coming out of it. it does not have mounting holes 180 degrees apart. it takes 3 metric bolts.

i screwed with the gauge wiing then never drove it for a while. i drove it to work one day and it quit on my way home, i found a burnt of wire on the firewall by the junction block. i fixed that, then one day i wanted to use it i made it about 1/2 mile out the road and it quit. i had the lights on both the times it quit. i got a jump start and drove it home with no lights. ever since then i've been trying to figure out what's wrong.

first i took the alt to get tested, it was bad. got another brought it home and put it on, wouldn't charge. i never messed with the alt wiring all this time, except for the gauges. got another alt, now it won't work. borrowed a neighbors and it works. i started re arranging the alt wiring yesterday. thought i had it figured out, came home today and it is making a buzzing sound, so i unplugged it and it quit making the sound. the truck would barely start, so it must have been draining the battery since yesterday.

here are some pics. hopefully you guys can figure this out. i think i need to use a resistor to create a draw to tell it to charge??? also the large wire coming from the alt was never hooked up, it was always the smaller ones from the plug.

more pics---http://s130.photobucket.com/albums/p276/YZEATER/85%20chevy%201-ton/

 

[dyeager535]

My first thought is you need a wiring manual, period.

That wiring is hacked up, no telling what else is wrong in there.

 

[bronc3buster842001]

The main lug needs to run straight to the battery. The big wire from the plug goes to the junction block,next wire should go to a ign hot, and the other to the gauge.

 

[YZEATER]

there are no gauges originally in this truck, only idiot lights. i have hooked up a water temp gauge, and oil pressure. i would like to hook up a voltmeter after i get this figured out. i've been using a voltmeter hooked to the battery posts to determine when and if it's charging.

i only want to use the original fuel gauge and speedo, and get rid of the rest of the wiring to the dash, or just not use it.

 

[YZEATER]

The main lug needs to run straight to the battery. The big wire from the plug goes to the junction block,next wire should go to a ign hot, and the other to the gauge.

that's all there is to it? the ignition hot wire, just put it to power that is turned on and off by the key? when i run the other wire to the gauge, where do i go with the other lug on the gauge, to a ground?

would i be able to tie the main lug wire and the big wire from the plug together, since they both are connected to power?

 

[ryoken]

yes, you can just the jumper the 10g over to the post that the big wire comes off of.. you also don't NEED to use the gauge terminal.. you can pick up voltage for the gauge anywhere in the ignition system... effectively making the alt a 1-wire hookup...

and yes, a volt gauge just has ign hot coming in to the ign post and a grd.. if you use an Autometer gauge do NOT put power to the "S" terminal of the gauge, you will nuke it... do yourself a favor and wrap it in black tape before you even put it in the truck...

 

[YZEATER]

i don't need any type of exciter wire/ small light bulb to tell this alt to charge? what happens with the other wires coming off the alt plug, nothing?

 

[bigblock72]

The light bulb is their primarily to drop the voltage to keep the alternator from backfeeding the ignition so the engine will shut off when you turn the key off. A diode or a 1 watt 100sih ohm resistor will do the same thing.

The other wires aren't needed on your application.

 

[YZEATER]

got it wired up last nite. i used a 194 bulb inline. used a test light and the one wire only lite up when the key was on. after it was wired together the light came on for a second then went off after it started. i'm not sure that it was wired up correctly since i got it, but it was working till the alt went bad.

thanks everyone.

o, one more question. i fryed the last alternator i got from advance auto. i'm using one from my neighbor. any way to fix it?

 

[lectric80]

The parts are readily available, but they won't be easy to obtain for the average person. Look for a local rebuild shop. A local rebuild shop should be able to rebuild it for pretty cheap.

 

[bigblock72]

Isn't the alternator still in warranty? Most places will warranty them for life if you ask real nice.

 

[YZEATER]

ya, it should be, but i already traded one in. and you only get 1 exchange. i'll go down and try to sweet talk the girl that works there(advance auto).