Alternator Not Charging

[Joe A]

1994 ls400 alternator not charging - removed the alternator & took it to a local shop that rebuilds starters & alternators - guy says it's putting out 14.6 volts -installed back into car not putting out voltage - checked the voltages with multimeter still no good - replaced the plug going to the alternator b/c it was brittle & falling apart- still not getting a charge - battery in good shape - checked all fuses & everything is good. Still can't figure out why I'm not getting a charge from the alternator - any help would be greatly appreciated.

[landar]

Did you check the main fusible link? Something like 120 amp feeding the battery from the alternator. It is not in a fuse box.That could be blown.

A little history on your problem may also help. You didn't, by chance, happen to jump start the car just before the alternator appeared to stop working?

Welcome to LOC!

[Joe A]

The problem started one night when the lights kept getting dim & the battery light came on. When I gave it some gas the light went off & the lights got brighter. I attributed that to the alternator. This only happened that one time that I'm aware - this is my 19 year olds car (first ride). So that's when I removed the alternator to have it checked out. I read all about the power steering pump leaking fluid onto the alternator. When I put in back in I could never get any signs that it was charging the battery. Brought it back to the rebuilder again and he says it putting out 14.6v. I never had to jump start the car to get it going& the fusible link checked out ok. The car does have an amplified sub woofer in the back- I don't think that has anything to do with it. Does anybody have any electrical schematics for this year lexus. I will double check the 120 amp fusible link and post back.

[landar]

Just an FYI, you do not have to remove the alternator and take it somewhere to check the alternator. You can make a fair assessment with a simple voltmeter at the battery and turning on a load (like headlights). Thats what I always do.

The reason I asked about the jump is that sometimes the leads will get reversed for a moment, sparks fly, and the fusible link gets blown. But the user does not realize this at the time. Another thing that takes out the link is touching the + main feed of the alternator to ground when removing the alternator. That only happens if the battery is not first disconnected. Did you disconnect the battery before pulling the alt?

I suspect that you have several issues and that you may have inadvertently caused one of them. Not sure though. Its hard to troubleshoot thru a little cat5 cable. ^_^

[Joe A]

I double checked the fusible link - All seems fine - What else can i check?

[landar]

I would start at square one. With the alternator back in the car, start it up with high idle (1500 RPM). Turn on the headlights. Put a voltmeter on the battery. Should be north of 13.5 VDC.

You could also check for continuity from the + main terminal on the alt to the + on the battery (System powered down). I would also check the ground on the alternator.

[Joe A]

I agree - im going back to square one with this. Thanks Randall - will post back

[Joe A]

I like to use local shops whenever possible. In this case it didn't work out. My local starter & alternator rebuilder could not diagnose the alternator i let him check twice. Turned out the alternator was not putting out the correct voltage. I took to pep boys & auto zone it failed both times - replaced with a new alternator and all is good - Thanks for you help in this matter Greatly appreciated!

[finespunflesh]

I went through this issue last year. Replaced my battery twice, replaced the seals and gaskets in my power steering pump, and finally replaced my alternator even thought it tested out alright.

Turns out that the connection from my battery to the pack of fuses that sends power out to the rest of my car was old, overheaded and very corroded preventing the power from my battery to reach my alternator, even though both the battery and alternator were fine in the first place. I had an on-site repair guy fix it in a matter of minutes with a new wire bypassing the old connection.

I had gone through months of my dash lights and all power flickering and draining my car over and over and leaving me stranded several times. Charging my battery over and over. It was awful but since that one little wire was replaced, my car stays charged and I haven't had any charging problems. It's been about 8-9 months I believe. I wish I could describe the pack that the battery was connected to that was corroded but it was right behind where the battery sits, and the only place the wire first leads to, but I'm pretty clueless when it comes to car stuff. Obviously. Trying to learn though, thanks to this forum ;)