Crazy Generator Red Light

[Llew Kinst]

OK. this is a strange one. Yes I have read all the other posts regarding generator lights.

First this is a 12V system using 912 regulator
This is what happens
1. Turn on the key, light goes on.
2. Engine starts and light goes out if RPM is under 800
3. Rev engine and light comes back on.

The generator is charging the battery and passes all the normal tests/
So I swapped out the regulator for a brand new one... no change
The swapped out the generator, tested it too.... still no change
Double checked all the wiring and it is all connected correctly. Check wire back to light and it is working fine. Hot wire to starter is fine.

Any ideas???

[Llew Kinst]

Oh one more thing. I am using the Zim 12V to 6V converter to run the gauges and lights

[Martin Benade]

Was it ever working correctly on 12v? I think a 12v bulb for the generator light would work properly with the converter only feeding various other things.

[Llew Kinst]

This is an all new car with new YZ wiring loom. The regulators I have tried are brand new, and the two generators came out of working cars. The bulb is a 12V with power coming directly from the ignition switch. Not going through the 6V converter. That was my first thought too. But It is not wired that way... but I will double check.

[Doug McDonnell]

Measure how many volts your battery is seeing when you rev up the motor. It is my understanding that if the battery voltage /charging voltage are way different then the light will be on.

[David Jones]

Llew, it sounds as though your 12 volts is feeding against 6 volts and as the generator voltage rises the light will go out as it hits 6 volts or so, then come back on brightly as it rises to 12 volts. Remember the bulb is not polarity sensitive so it will light as long as it sees any voltage across it. If you had an LED in there in the correct orientation it would only light when voltage was positive on one side but not on the other. That is one solution the other of course is to make sure the genny warning light bulb is fed with 12 volts on both sides so that as the genny voltage rises the light goes out at the correct time.

[Greg Bryan]

Llew - it sounds like maybe you've already checked, but you must have a separate 12 volt, switched feed to the bulb holder for the generator light, and have a 12v lamp in it. As stated above, the lamp goes out, or appears to go out, when you are close to balance with the generator output to the battery voltage.
You said you're running a 12-6V converter, so the wiring should be similar to the diagram where the original power wire is removed from the generator lamp holder and a separate 12V feed is attached.
You could run the 12V feed to the other two warning lamps, as well, as it is the temp and fuel gauges, assuming they haven't been converted to 12V, that need the 6V power feed.
Good luck!