Charging light

[eitech]

Good day fellas. Need some assistance again. So my charging light aka battery light comes on. It only comes on when the ac has been on for approx 10mins. I tried another alternator, tensioning the belts, checked fuses, harness wiring seems intact, same issue. If i don’t use ac the light doesn’t come on at no time. I haven’t tried another battery. When the ac is on, everything is turning with no slipping or belts sticking. The voltage when the light is on is approx 11.9v

[adnj]

You may have a high load or a the voltage output from the regulator is too low.

Voltage regulators typically need engines at about 1000 RPMs before energizing the charging circuit. You will need to look at current flow at the battery during run to see if thealternator is providing current at a low voltage or no current at all.

If the problem is only when AC is on, determineif the problem is only at idle or fit exists at higher RPMs also.

You may also have an unusually high resistive load at the AC clutch or fan. Disconnecting either will help to pinpoint those problems.

Depending on the age of the vehicle, checking all circuit connections, ground paths and wire insulation may be necessary.

[eitech]

You may have a high load or a the voltage output from the regulator is too low.

Voltage regulators typically need engines at about 1000 RPMs before energizing the charging circuit. You will need to look at current flow at the battery during run to see if thealternator is providing current at a low voltage or no current at all.

If the problem is only when AC is on, determineif the problem is only at idle or fit exists at higher RPMs also.

You may also have an unusually high resistive load at the AC clutch or fan. Disconnecting either will help to pinpoint those problems.

Depending on the age of the vehicle, checking all circuit connections, ground paths and wire insulation may be necessary.

It happens at idle (950rpm) and at driving speeds (>2500 rpm) with the ac on. Keep in mind i tried another alternator so i wondering what on the ac side i could address

[adnj]

Depending on the vehicle model, the ECM also controls alternator voltage regulation.

You will need to look at the voltage output at the alternator not the battery.

The AC clutch or fan control could be faulty.

You can look at the AC control wiring for a path to ground that would cause a voltage drop. There may also be a faulty AC control relay. These have a shunt to ground that may have shorted. Worn insulation, corroded terminal connections in the charge circuit, or burnt wiring can also cause a voltage drop fault.

You can try to eliminate the charging system by turning off the AC while operating with the fan and lighting on high. If that works, turn on the AC with the AC clutch disconnected. Then move to the fan.

[eitech]

So jus an update: About a week back i looked under the hood and saw some oil splatters all over the engine. I checked engine oil level but it was good. The oil itself looked like engine oil. I started the car to see if there was anymore leak with or without ac but there was no sign. Well you guys would never believe what the issue was. I went to an ac guy and as soon as i started to explain the problem, he said crankshaft pulley seal. I was shocked so i gave him the entire history again and he said the same thing. In addition, the engine oil seal was bad he said. He said at this stage with the symptoms i was having that pulley could have jus buss away. Well i was in panic mode. He put me on to a mechanic and i went immediately. He say doh rqce the car eh. Take it ez. Lol. So at the mechanic the guy mentioned that because the seal on the pulley was worn, it was creating a wobble hence when the engine got load from ac, the belts were slipping and thus my charge light came on. The oil i saw was a result of the oil seal being damaged from the pulley movement. Luckily he had a pulley, i got a genuine oil seal and he was done in about an hour. No more squeaking, or charge light and my ac cold. Talk about mis direction. I almost bought an ac compressor that day. Good thing i went by d ac man first. Well at least i got a spare alternator