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My alternator works great. The gauge is not helpful. I have an indicator light that never comes on and it has been suggested that I find one and have it installed to see it the light is the solution.

Where do you gurus point me to get a replacement?

If your 1980 152 is like mine then that light is not an alternator light.
It is a "Low Voltage" light and I hate it when mine comes on.

As far as the suggestion to "find one and have it installed to see it the light is the solution" goes
That is an expensive way to find out what the problem is.
Those lights go for around $40 and when I googled the part number most places said out of stock.

What have you done to try to get it to turn on?
One thing you can try is to turn on just the battery side of your master switch
and start your engine. starting this way may put enough load on the battery that the light may illuminate.
If it does, just turn on the Alt. side of the master and it should go out.
If it doesn't then you should get a volt meter and check what the voltage is.
I'm not sure how low it needs to be to light the light.

Also, you are correct stating that the amp gauge isn't helpful.
I have never seen mine show any deflection except for a couple of seconds after starting.
It normally sits right in the middle. If the alternator wasn't working it would show a deflection to the left(discharging).
If you start the engine and turn off the alt side of the master and turn on pitot heat,
radios and all other electronics and you will see a slight deflection to the left.
Remember it's a 24 volt system so these thing draw 1/2 the current of a 12 volt system.
Another thing to do is make up a volt meter that you can plug into the cigar lighter socked
and monitor the alternator's output.

If you happen to have a Zeftronics ACU.
Trust the schematic in your 152 Service manual first.

I do not have a light in the hole where the low voltage light should be. Twice I have had electrical system failure, and it sure would have been nice to have had a warning light. (I know I could have been scanning the ameter throughout the flight, but I wasn't.) I'm going to get the IA to see if we can remedy that at the annual in March.

Probably the biggest bang for the buck regarding the electrical system monitoring would have to be adding the EI volt/amp meter.

It's an easy install, not that much in terms of cash outlay and it's digital for both volts and amps which does away with the guess work associated with a needle and the angle your eyes look upon said needle.....it has a warning light as well to draw your attention to it if your scan isn't up to snuff.

It's the instrument in the top right corner in the picture.



Jim

^^^^^^^ +1 ^^^^^^^

If you decide to upgrade, buy the one with the internal shunt.

I'm reminded once again what a beautiful panel you have, Jim!

I like. thanks.