M20F Gear Indication Issue

[CanadianMooniac]

Hi Mooney gurus, I am looking for assistance with a strange intermittent gear indication issue.

I have a 1970 M20F Executive, equipped with electrical gear and only a "Gear Up" and "Gear Down" indication lights, with the illuminated floor window. I am experiencing the following issue:

1. On the ground, all gear swings are successful and the indications are all correct.
    
2. In the air, the gear up indication functions correctly. 
    
3. When lowering the gear in the air, the green gear down light often fails to illuminate, as does the light in the floor window. However, the gear does extend (confirmed by video in the air) and the stripe lines up in the floor window, although the light does not come on.
    
4. Recycling it several times in the air will eventually cause the gear down light and floor window light to illuminate.

Does anyone have any insight into this, and specifically why this issue cannot be replicated on the ground?

Thanks for any and all assistance!

 

[PT20J]

The gear down limit switch is a double pole switch. One pole drives the actuator so it will stop when the gear is down and the other pole drives the lights. Perhaps the switch is going bad. No idea why it would do it only in the air. 

[takair]

I would get it on jacks and have the rigging checked with the belly panels removed.  There are a few threads around here on what can go wrong.  One thing that might cause this is the pushrod bending under compression.  This can potentially result in gear collapse.  

[Yetti]

There is more weight on the gear on the ground.   So the gear down switch is a bit out of adjustment, would be my first guess.   Flush out the switches with some contact cleaner.

Also you may have a loose ground wire or loose wire that is getting moved around.   The gear switches are in the center section on the right side in this video.