Engine light on with lights on

[rickburt]

Hi
I have a VX commodore and the engine light comes.
It comes on when the following:-
* if climate control in on higher than 3 with the lights off.
* if the lights are on the air con has to be off to keep the engine light off.
* If i have high beams on it will stay on until the high beams are turned off.
If any 1 can help me with this it would be greatly appricated.

[rickburt]

i also went into the diagnos on the dash and it was any where between with highh beams on 11.9v though to about 13.5 with all lights off air conditioner off and radio off.

[accentstencil]

The best thing to do would be to check for fault codes. Do a search on how to read fault codes.

[Tsunamix]

Ok 2 things stand out.

With everything turned off - Minimu Voltage should be in the High 13's/ 13.8 Nominally, engine running. this is the Float charge rate for automotive systems.

This is The output of the alternator, and a few amps - maybe 20 amps max, which is used to run the system and float / charge the battery. (idle)

If It drops below 13.0 engine running with everything on, 2 things are happening. 1 - the alternator is buggered and not providing enough ampage to run everything at idle as wella s charge the battery, and the battery is being asked to make up the difference, as the battery is half flat, or 2, the battery is stuffed and can't make up the difference.

As you can see, it can be hard to tell which is which wiothout testing. Rip your battery out, charge it overnight and test its voltage in the morning. anything under 13.8V = Stuffed battery. There are 7 x 2v dc cells in there with 1.85V End of life capacity. Thats 12.95 total at End of Life.

If the battery is ok, chuck it back in, start it up, run it up to 2000rpm and measure the Voltage across the battery. Should be 13.8VDC which is enough to trickle charge the battery. If it's below thw 13.8, your alternator is doing stuff all and the battery is providing power to run th eentire system.

The alarms you are getting will be PCM DC bus undervoltage (which will throw you Limp home mode if they drop far enough).

[rickburt]

the battery should be fine as i only replaced it 3 weeks ago along with the voltage regulator and with the reds on the little screen is sayin 12.2 v thanks