Topic: I really need your help...

[Steve97TJ]

My battery died on me yesterday and i took it to the auto parts store to get a new battery and the guy who worked there said that the battery was fryed and he thought it was the alternators fault because it looked to be going downhill but it should last me a little while. Well it ran fine today and i was getting gas across the street from the same store and my batteries dead. I run over there buy a new alternator and get the guy to run across the street and jump it off because i thought that it would solve the problem. I go home took me forever to get/wiggle it out but i finally did and got the new one in there.

Problem #1: there is a plug that goes into the back of the alternator, beside the power wire im guessing that didnt fit in the new alternator because the plug pattern was different. What is this and do i need it?

Problem #2: I got my roommate to jump me off and i rode it around the neighborhood for a little bit but my lights were pretty much none existant and its 12 here so its pretty dark. I let it sit there and idle for about 10 mins to see if it would charge up the battery and when i shut it off and try to cut it back on, its dead and wont do anything. Whats wrong with it? Did i do something wrong or was the engine not worked hard enough to make the alternator turn on?

I have to get up in the morning and drive back home (3 hours) on the interstate so i really need to fix this.

[Doof]

what kind of car is it?


i assume that it is a ground of somesort but i am prob wrong

[Duffil]

your alternator is not charging...if the plug doesn't fit, they gave you the wrong unit...yes you need it.  get the right alternator, and charge the battery while you are swapping it.  An alternator is not designed to charge a battery, just to keep it charged.

[Steve97TJ [OP]]

Its an 82 toyota 4wd with 22r.

What is the plug? I wasnt sure, but thought it just had something to do with my gauges or something. I didnt source it down to see where it went to but i guess i will do that tomorrow. I will take it back tomorrow morning and make them change it and put a new one in.

If i get the battery all the way charged up, and they dont have the right alternator in stock, could i possibly just drive it home like that as long as i keep it running? Im not sure how carb'd engines run that much, and it could be a stupid statement, but i dont see needing the battery that much as long as im not trying to crank it. I guess itd power my turn signals, but ive counted and theres only 7 turns between my house in chas to my house in abv and thats stretched over 250 miles.

[Duffil]

1. you can but by running your battery all the way down, then charging it back up, you will kill it.
2. the plug is an field wire to make it charge, voltage out to your regulator and one to your charge light, IIRC.
3. you need the battery to provide power for spark.  it does this on ALL engines.  Your alternator keeps the battery full and helps in high amp draw situations.
4.GET THE RIGHT UNIT.

[oddball]

Long story short that plug needs to match to work if the plug doesnt fit its the wrong alternator

[Steve97TJ [OP]]

Alrighty then. i guess that solves that. It pisses me off because its got a 3 prong thing and they are almost identical but a few things are holding it back.

Anyways ill be jumping my truck off and taking it back up there in the morning. Thanks.

[YotaJosh]

When you buy the new alternator, be sure to know the plug markings (LEF, FEN, etc.) and how many wires go to your regulator (5 or 6). Sometimes the plug color (green or black) is helpful to know. It's also wise to go ahead and get a new regulator as well.

Also, a good "is it working" test is to get the truck running, let it idle, and disconnect the negative battery cable. If it still runs, then the alternator is charging. If it dies, then the alternator isn't working.

I recently put a 20R out of a 79, into an 82, and the alternator wiring didn't match up, so I had to get a new alternator that matched the 82's wiring harness. I'm sure there's a way to make them work, but I didn't feel like hacking up any wiring.

[TIMS89CRAWLER]

i use a GM one wire alternator on my truck that just has one wire that goes to the positive on the battery... plus its an 85a. alternator so it rocks anyway... pretty easy to make some brackets fit, they are easy to find, and cheap as hell....thats just where i went after killing multiple toyota alternators.... i mounted my GM one much closer to the top of the engine to keep it out of the mud and water too.... just a lil thought for ya

[Duffil]

Also, a good "is it working" test is to get the truck running, let it idle, and disconnect the negative battery cable. If it still runs, then the alternator is charging. If it dies, then the alternator isn't working.

just so you know, on any vehicle with a computer, that's a really great way to fry your ECU.

[TIMS89CRAWLER]

to do that test you pull the positive terminal off anyways.....not the negative