truepenhead@gmail.co

i have an 86 btoyota pickup that i've picked up recently and runs good but i've been having troubles with the battery going right dead when the truck is running. the funny thing is it doesnt go dead when the truck is off just when it is running. i noticesd on my dash that the charge light and brake light are on when it is running and im shure there's a connection between the two. so i cant quite figure out why my battery keeps dying and im guessing it's a short somewhere oin the truck but dont know where to look. so if anybody has any good idea's of where to start or look that would be awesome. thnx.

Fink

What engine?
Stock battery?
Any wiring mods done to the truck?
What was the last thing done to the truck before this started?

Fink

schmooot

sounds like your alternator is not charging.

Once you get the truck running (by jumpstarting it I assume) the battery should get cut out and the alternator then takes over all the trucks electrical needs.
In your case the alternator is not charging or may be charging very little either way most of your electrical is running off the battery and will kill it shortly because the onyl juice it has is what it got from the jump

aviator

If the engine does'nt die on you I'm guessing that there is a dead short to ground somewhere in wiring, it also could be shorting across the top of the battery pole to pole if there is a lot of moisture up there, final guess would be a faulty battery, My 87 22r had that problem once... boost it to get it running and everything was good, no problems, shut off and have to boost again... the Batt would not hold a charge... it was one of those "maint. free" types... when I switched it out the thing was basically dry inside, no sloshy feel at all... I changed it to a batt. I could check and top of periodically... a big ass 1000cca tow truck battery actually ... I never had an issue again even after leaving the lights on all day...

Still using the same type of Batts. today in my current truck I was able to drive 25 miles (40kms) to work one day with no alt. at all just batt power... [alt had crapped out on me just as I got on the highway]

truepenhead@gmail.co

it's a 22-re 4 banger and i had done a engine swap but i dont know if it was happening before i did the enghine swap too. i've checked multiple batteries and it did'nt make a diffewreence. i tried boosting it but boosting it just started it up and once i took off the boosters it slowly dies. aviator i think ur right about the short cause the truck wont boost and stay running and thew fact that my charge light is on along with the brake light. so i dont know if it's has a connectiuon to my brakers if i have a short in my brakes or not. where do u think i should start lookin at.

Yoda

Alt out will cause both lights to come on.

khoopes

The electrical charging circuit is probably not that complex. Just look at the schematic and get a voltmeter/ammeter.

If you don't kow how to use these find someone who knows electricity and has the multimeter. First do a voltage check on the battery with the truck running. Probably the alt is bad. Should read around 13.8 volts on the battery when the truck is running. less than 13.5 the alternator is probably out.

I think the brake light comes on with the alternator being bad, my 88 22RE truck had the alternator go out recently... and I lost the alternator belt in a separate issue- I think the brake light comes on to.

Charge the battery on a good charger for at least 2 hours and then do a load test on it before installing a new alternator or premature "alternator death" may occur.

truepenhead@gmail.co

really i never would have guessed. i'll go and try that right away i hope that is my problem. i've never used a mulitmeter much but i know how to check voltage on my battery. how would i get ahold of a schematic?

truepenhead@gmail.co

ok i checked the battery(with a good charge no need to boost) when it was running with my multi meter and it read 11.76 V.

aviator

Okey dokey then... its yer alternator that's kaput lol... fun times ahead for you... if you have the 4cyl [I think you should] there is a bracket kit you can get that will allow you to upgrade the alt. to a big 190amp GM unit [if you want to go that route]. or there are several options to choose from in the stock alt. case size. Changing out the alt is relatively simple just a PITA is all... don't forget to get a new belt at the same time... good luck

truepenhead@gmail.co

thats alot man thats saved me on big head each.i do have a 4 banger and curious to how would i get ahold of a bigger alternator braket for my pickup?

aviator

There was a link someplace on here... check Wabfab maybe?... or try a search for 22re alternator... you'll get a lot of hits and I know there will be the link you need somewhere in there...