Annunciator lights don't come on with test button

[FlyDave]

My annuciator panel lights have exibited the same problem in both of my last flights in the last 5 days:

They don't come on with the test button when on the ground but they do come on when you push the test button with the gear up when flying. The "Gear Down" stays on when on the ground but that's the only life in the panel with the gear down. I believe the "Gear Unsafe" light comes on when raising the gear but I don't specifically remember looking for that.

I had to pull the glarsheild off last week to re-install the rebuilt attitude indicator so I'm not sure if I did something then. I asked my mechanic about it and he said we'll look through the wireing diagram to troubleshoot it but he won't be available until Monday. He also said that it almost sounds like it could be tied to the squat switch on the gear - sounds possible to me.

Any ideas on this?

Thanks,

[mjc]

Quote: FlyDave

My annuciator panel lights have exibited the same problem in both of my last flights in the last 5 days:

They don't come on with the test button when on the ground but they do come on when you push the test button with the gear up when flying. The "Gear Down" stays on when on the ground but that's the only life in the panel with the gear down. I believe the "Gear Unsafe" light comes on when raising the gear but I don't specifically remember looking for that.

I had to pull the glarsheild off last week to re-install the rebuilt attitude indicator so I'm not sure if I did something then. I asked my mechanic about it and he said we'll look through the wireing diagram to troubleshoot it but he won't be available until Monday. He also said that it almost sounds like it could be tied to the squat switch on the gear - sounds possible to me.

Any ideas on this?

Thanks,

[FlyDave]

This turned out to be a ground issue. We ran a new ground from a screw in the annunciator pannel case to the airframe and that fixed it.

[tomslupilot]

I have a problem where I can't seem to get the annunciator lights to test with the push-to-test button.  I checked the bulbs and they're all good.  The gear lights work (up and down) respectively but none of the other 3 lights seem to work (overvoltage, Lo Vac, and Hi Vac).

When you press the push to test button should all lights come on (Gear Up, Gear Down, Overvoltage, Lo Vac, Hi Vac)?  

When you power the airplane on before starting the engine, does the Lo Vac normally light up?  (Mine does not)

Any ideas for troubleshooting?  Working with my mechanic as the airplane is in for the annual now.

Thanks,
Tom

Edit: Just realized this is in the wrong forum for me... 1969 M20C so posting on the vintage boards.

[carusoam]

Expect that the test should light all.

I am not aware of any logic that would allow for the lights to be absent when their conditions are met.

 

Best regards,

-a-

[Cruiser]

did you check the switch contacts behind the little red button?

[M016576]

Quote: FlyDave

This turned out to be a ground issue. We ran a new ground from a screw in the annunciator pannel case to the airframe and that fixed it.