justanother4x4

I have recently been having my battery and brake light come on and off for a little while and when It would come on the volts would drop on my meter in the dash. But then sometimes I would start the truck and no light and it would be days before it would come on.
so after just thinking maybe it was a belt that was slipping i just kinda put it off, but over the weekend I installed some shocks (procomp es3000 which by the way are a nice ride) and went for a test run and that light came on and has stayed on since then, so i did some research and thought that the alternator was at fault so I took it off and had it bench tested at advanced auto parts, the alternator was perfectly fine, so I installed it back, drove the truck up there and had them test it again, along with battery and starter test. Everything checked out except with the alternator in place now the battery is not charging, the machine says that there is an interuption in the wire to the battery from the alternator. I guess my question is has anyone had this happen and where should I look first? I have an idea that maybe the 80amp main fuse under the hood might be to blame but I have looked at most of the wiring and have found nothing. I also took apart the alternator to look at the brushes and they look great. Is there another fuse or fuseable link I am missing. Thanks for the help and sorry I had to write a short story to get this out, but I wanted to make my self clear on everything I have done.
:cry:

Yota4runner

There is a 7.5amp charge fuse under the hood. Did you check that?

I would start looking for breaks in the cables, corrosion or a bad ground.

2ToyGuy

Especially corrosion that may not be readily visible, corrosion down in the insulation of the cables, or under ground connections, things like that. I got tired of corrosion down the insulation of the battery cables constantly giving me fits, so I replaced them completely when I went to Optima batteries, along with the terminals. No problems since.

justanother4x4

i have not seen any corrosion yet, but is that fuse in the box under the hood? On my previous car, vw GTI was notorious for electrical problems but I ran two seperate positive battery cables, one went straight to the starter and the second went to the alternator, do you think that would be an effective solution? And there was some slight benfits to doing so as well, brighter headlights and smoother idle.

callmej75

I had the same thing...turned out my brushes were wearing thin. Light would go out..come on...sporatic kinda..

justanother4x4

i wish it was the brushes, i took apart the alternator last night and the brushes were fine, no unusaual wear and had plenty of meat left on em.

callmej75

Just reading through your original post...I'd definately check all cables. Better yet...replace them all and the ground too. Make sure the ground wire is grounded to the body too at the battery.

2ToyGuy

Definately look at the grounds closely. The one between the battery and the engine, the battery and the body, and the engine and the body, at the back of the head. That one doesn't really do much for the electrical system, but it will prevent the head from turning into powder from electrolisys

justanother4x4

i have just finished cleaning up and replacing all of the wires that i might have problems with, the truck starts perfectly and runs great but its still running off of battery power. I ran my volt meter between the battery ground and the output post on the alternator and it read 12.1 while the truck was running, which leads me to believe even though the machine at advanced auto says there was nothing wrong with my alternator I think i may just get a rebuilt one and stick it in and see if it fixes it, if not I will just return it.

1leg1der

justanother4x4 i seem to be having the same problem as you, accept no lights come on. I have replaced the battery had the alternator checked twice at advance auto parts checks good. Battery goes down about every 5 to 7 days sooner if driven with headlights on. When problem first begin i noticed that with headlights on after dark while acclerating lights would get dimmer, let off acclerator lights would get brighter. opposite of what should happen.
1990 22re 5 speed 4x4

justanother4x4

have you replaced the alternator yet? Maybe the machines at advanced auto parts just dont understand the problems that these alternators have. I am now strugling to get to the parts store just to order the stupid thing, i might endup taking the bus tommorow to work and the parts store. The san antonio public transit system sucks, looking forward to a great day tommorow.

1leg1der

Haven't replaced alternator yet, but may do that in the near future. Just giving it a recharge along.

justanother4x4

ok, now im a little frustrated, i started just throwing parts at it. I put a new alternator in and nothing, so now i am replacing the belts which should make a difference but i doubt it will make the alternator not charge. I think i might just set my yota on fire.

94x4

Have you checked/replaced the cables yet (as suggested), particularly the ALT to BATT main charging cable ??

justanother4x4

is the power wire from the alternator to the battery have an inline fuse or go thru the fuse box under the hood? That is what I plan on doing tommorow, but i am thinking about getting some 8 guage wire and running a wire straight from the battery to the alternator.

94x4

Use 4 gauge.

Also, have you checked out the "Big 3" grounding wire upgrade by 4Crawler? If not, you should..., major inprovement.

justanother4x4

woooot! i fixed it, after I put a new alternator on it, the problem did not go away, so I checked some wiring diagrams and check the white wire from the alternator to the fuse box. there was a burnt wire inbetween the alternator and where it hooks to the little junction box with the 80 amp fuse. A little hint for some one looking to get that fuse out, the whole assembly that the wires connect to slides out of the bottom of the fuse box and is held on with that little clip on the side.