Hi guys, last week i was going to work and the car turned on the battery light, when I stopped I tried to start it again but I ran out of battery ... I changed the ic regulator but it's still the same, the battery has 12.40V and when it is working is between 12V 12.70V

The problem is the alternator isn't it?

The red light comes on when there is more power going out of the battery than into the battery, so yes, things weren't charging. You have the 12volts a battery stores energy at, but no stored energy behind it, it has no amp-hours stored. Put it on a charger overnight.

If you start the motor & check with the multimeter you should get over 13V. If you don't, check the wires and wriggle them for fractures or loose connections, then pull the alty out and strip it to check the carbon brushes, they wear away while it is running. The other likely suspects are the diodes that convert AC power into one-way DC, they burn out over the years. Alternatively, whip the alty out and drop it into an auto electrician or similar.

15 hours ago, altezzaclub said:

The red light comes on when there is more power going out of the battery than into the battery, so yes, things weren't charging. You have the 12volts a battery stores energy at, but no stored energy behind it, it has no amp-hours stored. Put it on a charger overnight.

If you start the motor & check with the multimeter you should get over 13V. If you don't, check the wires and wriggle them for fractures or loose connections, then pull the alty out and strip it to check the carbon brushes, they wear away while it is running. The other likely suspects are the diodes that convert AC power into one-way DC, they burn out over the years. Alternatively, whip the alty out and drop it into an auto electrician or similar.

I did it last night, when I did the alternator test I had left the battery charging all night and the voltage was still with this voltage 12.65V with the engine running. 
Today after work I will take out the alternator and take him to the auto electrician, to remove just need to unscrew to bolts one on top and one in bottom right ? And for belt they come out easy ??
 

Yes, take the wires off first then one bolt on top, and two on bottom.

On 1/21/2021 at 10:14 PM, altezzaclub said:

Yes, take the wires off first then one bolt on top, and two on bottom.

I already changed the alternator and measured the battery with the car working and it’s measured between 13.70v and 14v bit the battery light is still on. Is it the battery that broke down ?
 

No, the battery should be fine, it is not in the ignition light circuit. Was it a new alty or a reco, or just one out of another car? It sounds like the alty is charging OK, maybe its a wiring issue.

The charge light circuit looks like this-

 

or like this-

 

which shows both internal & external regs.

 

Have a read through this too-

http://wilbo666.pbworks.com/w/page/39441708/Toyota Alternators

 

 

12 hours ago, altezzaclub said:

No, the battery should be fine, it is not in the ignition light circuit. Was it a new alty or a reco, or just one out of another car? It sounds like the alty is charging OK, maybe its a wiring issue.

The charge light circuit looks like this-

 

or like this-

 

which shows both internal & external regs.

 

Have a read through this too-

http://wilbo666.pbworks.com/w/page/39441708/Toyota Alternators

 

 

Thanks for the help men !

I will take the car to the auto eletrecian next week, I don’t know to much about that ... 

Fair enough-  if you have an external regulator that will be the next most likely culprit. Both my flatty KE70 & the slanty had internal reg altys, but maybe they had been replaced and factory was an external reg. Your original alty may be good and the external reg has died.  See which setup you have, the external reg is a small black metal box with wires running out of it.