Dave80pickup

Do you have stock '80 pickup with the blue, green and black wires from the regulator going into the green female plug to the alternator? If so, could you pop the hood and tell me which wire goes where in the plug? My plug broke and was replaced by 3 separate flag connectors. That was fine until somebody got them scrambled. Now the alternator doesn't work. Nothing online or in the manuals about this, and they changed the colors every year. (Only the '80 has blue, black and green, and the diagram just shows them all going to the alternator, no pinout given).

I'm up the creek until I can get the information, because there are nine possible ways they could go in and some could damage the system. This is the square green plug that has two vertical slots and a horizontal one above them. See photo.



Thanks,
Dave

kawazx636

iTrader: (3)

What color are the wires that went to the plug and do you have a volt meter??

Dave80pickup

The wires are are Black, Blue, and Green. The black and the green are about 16 gauge, the blue is 14 gauge, or the same difference. And yes, I have a volt meter.

After posting here I checked with an auto electric shop. The guy looked it up and and gave me a set of connections based on the terminal letters F-E-N on the alternator itself, as follows:

F <--Green
E <--Black
N <--Blue

(He actually said "brown," not "black," but there are no brown wires. May be a lost-in-translation thing on the schematic. The Chiltons schematics all say black.)

Anyway, I made the connections he specified, but the charging system still doesn't work, The charge light is still on and voltage across the battery poles is about 12.26 and gradually goes down while the engine is running. There is the possibility that the misconnections damaged the alternator and/or regulator.

Thanks,
Dave

kawazx636

iTrader: (3)

The wire colors are pretty finicky with Toyota so your best bet is to find somebody to take a picture of the wiring for a 1980 green plug alternator. But I think you are on the right track because the 2WD trucks in 83 used the FEN plug. Here's the wiring that I have in my FSM:

L (Lt Blue) wire: From "N" to voltage reg
G (Green) wire: From "F" to voltage reg
B (Black) wire: From "E" to voltage reg
W (White) wire: From "B" post to battery (should be red .85 fusible link on this wire at the battery - it will likely be in plug with a green .5 fusible link)


If you have it right, BEFORE you turn on the ignition:
-The White wire ("B" post) should be hot

When you turn to ACC:
-The charge light should and either the Blue wire ("N" terminal) or the Black wire ("E" terminal) should be hot - not sure which one though

When you turn engine to the ON position:
-The Green wire ("F" terminal) should come hot

Before anything though, I would check to make sure your fusible links aren't fried and that your charge light relay works - you truck will not charge without either of these.

Again, I'm an '83 guy so I'm not certain of the wiring above, but I would try to tone everything out with a multimeter before you put power to the system.

BTW, B = Black, Br = Brown in Toyota wiring

Dave80pickup

Thanks again. Your mapping of the colors to the F, E, and N terminals corresponds exactly to the one given by the guy at the auto electric shop (apart from that "brown" business, the wire that isn't there). Also, the Chiltons shows the same three colors for the 1980 and 1983, so I think I can be pretty confident now that this is the right mapping.

Re voltage, I assume you mean battery voltage by "hot" and that you're measuring at the plug with the plug out? In that case, I'm getting only very small or no voltages regardless of the position of the key. Since your last reply, I took out the alternator and had it tested and it tested 100%, so this points to the regulator, possibly it got fried by the incorrect wiring. The CHG light does work, this is how I first became aware of the problem. The trick is to get it to go off, showing the battery is charging. Before I do anything more, I'm going wire in an actual plug. The current arrangement has spliced-in wires in random colors which I've been having to trace back to the original colors each time I disconnect and reconnect, making it much too complicated.

BTW, this and other problems started when I had a friend replace 500.000 mile engine with a new used one--he's conscientious and does good work but he's a little unsophisticated when it comes to electricals and carburetors. So another problem is that the carb doesn't fast idle since the swap. You say you're switching to a Weber, but if you know much about the original carb, I'm putting in a posting in a new post about that today. Please give it a look if you think you can help.

-Dave

Sdmeitzner

So did you get it all working?

Ive got a 78 with the same alt. plug, and just rewired mine in the last month or so. I had so many voltage/electrical problems, I had to go thru the whole system. (all better now)

Dave80pickup

I'm getting there. Alternator has terminals F-E-N, Wiring appears to be F<--Grn, E<--Blk, N<--Blu. Is that what you have? (Chilton shows the same wire colors for '78.) Still doesn't work, so I took out the alternator and had it tested. It passed, so it's probably the regulator burned out by the misconnections.

Nelle22

I have a 79 with basically the same problem as the guy with the 80. Someone pulled the alternator out without marking where the three wires go...completely confused and can not find a wiring diagram to save my life!!! Can any one help?? Mine is a L-E-F

Lons81

iTrader: (2)

According to my 81 alternator plug wiring,
L= Yellow,
F= Green,
E= White/black.
It seems that the F & E wiring is pretty consistent in color code, with the L wiring changing through the years

Dave80pickup

Turned out the scrambled wires to the alternator "green" plug were only half the problem. Thanks to replies from here and elsewhere i got them unscrambled, but the alternator still didn't charge. I started to suspect the inputs to the regulator that aren't part of the plug. One is a red wire called "IG" on the schematic below. You can see it's the only source of voltage for the alternator field terminal from the regulator and a separate schematic showed it comes from the "engine" fuse on the fuse block. I checked the fuse and it was blown. I replaced it and now the CHG light goes out and the battery charges.

I'd wondered about this fuse before, but thought, well the engine runs, so.... Could find absolutely no information anywhere on what the fuse controlled until I puzzled it out from the two schematics.

Calum Wass

Hey Dave,

I am have some very similar issues. hoping this thread could lend some advice.

I.have the charge light, huge voltage drop and a parasitic draw close to 6amp lol

Did you ever investigate the wiring from the battery to the back 80 amp fuse link?

I feel this is where the last guy got them muddled up on my 85 pick up
Cheers!



Is this wrong ?!? Clean white wire going right is hot from positive post on battery...making the smaller red wires unfused. ? I think the reds go the the 40,30(looking rough),10(blown) amp fuses in the same box ... I believe the two white wires on the left run to altenator . Should anything other than postive from battery be on the un fused side of this 80amp ?

Brino

I bought an 81 recently that was somebodies Rock crawler project. It has some botched wiring. Most of the truck has been rewired. I can’t get this thing to charge. Are there any alternators with built in regulators that will drop in and not require a different bracket? A keyed hot wire and a battery wire would make this a lot easier.