Dee_Lexus

Ok, so I had left my lights on while in the store shopping for less than half an hour. I go to crank my car and it was dead. I got a jump off and life was good. I go get a new battery to replace the old battery and drive home. I cut the car off then crank it again and the car is dead with a new battery. To make a long story short everytime I jump off the car and drive all of the lights on the dash comes on then the car will cut off. The alternator test was good. I don't know what the problem could be. Will someone please advise?

bob2200

I think the headlights on my RX300 go off a little while after I take the keys out of the ignition. I suspect the test that was conducted on the alternator. It should have been a charging system test and should have found the problem.

It's possible the new battery was purchased in a discharged state. It takes a good drive to charge up a battery. Normally a new battery comes with a pretty good charge, but maybe the one you got didn't have a good charge.

If you can, charge the battery with a battery charger. If that doesn't help, or you can't do that, the next step, in my opinion, would be to take it somewhere for troubleshooting where they know what they are doing. It should be easy to find the problem.

Dee_Lexus

I made a long story short...

On the day that my battery died, I purchased a new battery and once that battery was put in my car the car didn't start. Some trouble shooting occured and it still didn't work so I return that new battery and had my old battery put back in. The next morning I went to another place a had another new battery put in my car and the car cranked immediately and held it's charge until I got home. Once I cut the car off at home, I tried to crank it and it wouldn't turn over. The lights would not come on, the horn wouldn't blow. This was Wednesday, the day before Thanksgiving. I had to go out of town so today I tried to drive it to the dealership so it could be worked on first thing Monday morning but after I got a jump off and tried to drive it is when all of the lights came on and it would cut off. I guess I will have it towed off in the morning and find out the problem. I will keep you posted.

RX300TC

With the addtional details, it sounds like an electrical system problem that is killing the batteries, or they are not being charged while driving.

Dee_Lexus

An electrical problem sounds expensive. Is it?

RX300TC

That's like asking a doctor "My arm hurts, how much surgery will I need?" before he even examines you. It could be something simple, maybe not. There is literally several hundred feet of wire in a modern car, can't say what it is until someone looks at it. Let us know what the shop says.

code58

It can be very expensive. Having said that (didn't mean to scare you) I wonder if the problem isn't a poor connection somewhere in the main power for the car. I say "poor connection" because I don't necessarily mean "loose connection. You should have a main fuse in the RX. That will be a fuse of about 175 AMPS that shows in the fuse block under the hood but gets BOLTED in, not pushed in. It probably isn't blown, but could be corroded where the contacts are bolted. You need to get a tester and follow the juice all the way from the battery on out to find where it is losing continuity when this happens. If you have a sharp mechanic, he'll find the problem in a hurry, that's what he's used to doing. If you're unlucky and get a dishonest or not to bright one, all bets are off. I personally don't think it should be to hard to find the problem. Put them on a leash, don't give them a blank check or they, not you, will fill in the numbers. NOT GOOD!

I don't know if you have auto electrical shops in your area, but if you do and they are well experienced, that might be the way to go.

JohnLX300

iTrader: (2)

I had a problem with my RX300 battery. I left the dome light one for over a week. Since I don't drive the car much it completely drained the battery. I jump started the car drove it for and hour. Turned it off, wouldn't start back up. Jump started it again. Bought it to Advance Auto so they could check the battery and alternator. The guy first stated that the battery needed to be charged...duh...and I have a bad alternator, which was only a year old. He claimed because of the "excessive ripple" that the diodes were bad. After some internet forum research I learned that the battery in a completely dead state needs to be fully charged with a car battery charger, it can't be charged in the car...cause of the excessive ripple. Did this and it worked. I remember from years ago a mechanic told me to check to see if the alternator is bad, disconnect the battery when the car is running. If the car stays running the alternator is good, if not it is bad. Just thought you may want to try it out.

bob2200

NOT a good idea with today's cars. When cars had generators instead of alternators and no electonics, it was sound advice, but that was over 30 years ago.

Dee_Lexus

I took my Lexus to the Toyota Dealership to see if they could figure out the problem and so far they have tested the alternator and found it to be good shape. They are going to troubleshoot tomorrow to find out what is causing the problem. I will keep you posted.

JohnLX300

iTrader: (2)

I am just wondering why this isn't a good idea with today's cars? What are the effects of doing this?

Australian

I will guess and say whether or not they tested the alternator it isn't charging.
If they took it off the car and tested it there is less strain without the belts so it could be bearings in the alternator. If they just tested it with a multimeter and it isn't pushing out 14 volt eg 12.9 volts it needs brushes replaced and is not working correctly. I will tell you one thing for sure it is the alternator the reason is the alternator goes directly to the battery on every car it doesn't go to a computer or anything else on any car it goes direct to the battery.
So it is one of these things

The alternator is broken. Bearings or brushes often if bearings ok it is working then siezes
and belt just slips around it often without lots of noise
The earth cable is broken the wires look fine but have broken inside the insulation due to battery wobbling about not secured or getting brittle due to short and heating up.
One of the wires has come off or loose on back of alternator and isn't charging until it reaches 3500 revs or not at all depends which wire.
Some sort of other bad earth likely car radio or amp not turning off when ignition off and sucking the power all the time.

If this happened to me my first thing would be to buy whole new alternator if not a second hand problem is alternator is reason most cars break down so if at wreckers often only thing broken on car so best to buy more than one.
If your convinced putting in a new alternator is fruitless then check whether the new battery keeps draining when everything is off.
If it appears to go up that is normal a battery will charge itself a bit as the cells line up properly. If it goes down you have a short circuit.
If nothing happens when engine is off then check the earth lead itself there should be earthed to BOTH the chassis and engine. If jumper leads can't substitute for an earth and work then it is in the harness between the alternator and the battery then try run jumper cable from alternator to the battery to see if that works if so it is harness if not...
If you try all of these and cant find a solution i will join you scratching at my head but i would bet money that the alternator has a problem even though it tested okay.

code58

One thing I did forget to mention is the possibility that the cables are corroded down INSIDE the insulation. It does happen, it's happened to me. You don't see it unless you pull the insulation back a little with a mini screw driver. I would look for loose or corroded connections from the battery out. Could be other things, but that is one of the FIRST places to look.

Australian

The car will either continue to run and tell you the answer or stop regardless without a battery connected no real harm it just can't be really used as a troubleshooting idea if it stalls.

Dee_Lexus

Okay, so I got my car back from the Toyota dealership and it was determined to be the positive cable needed to be replaced. Problem solved. My car is running great. Thanks to all for your responses.