gear push to test lights not working...

[funvee]

Hi everyone,

 

I haven't been on here in quite some time because my Mooney has been zipping along swimmingly over that last year... It got me through my CPL and the IFR part of my MIFR rating and has me closing in on my 500hr point, but today I ran into a new issue.

 

When preflighting, I noticed that both the gear down and gear up lights didn't function.  I borrowed the bulb from the working Vac low light and tested both of them but they still didn't fire up.

 

I checked all of my breakers and all were good as gold (from appearances).  I thought I might have a failing breaker but I can't find out which breaker controls those two lights.  

 

So, my questions are:

 

C) Does anyone know which breaker those two are on?

 

J)  Does anyone have an idea of where else in the system it could have failed so that both lights won't light when pushed to test?  I thought it must be a ground to those lights but figured I'd see if anyone else has invented the wheel before I go off and do it again.

 

 Thanks for any help!

Shawn

[carusoam]

Shawn,

If we give you the answer, how do we know you won't dissapear again..?

Your going to have to give something back.

Sorry, I don't have an answer to your question, but...

These are the two lights, green and yellow...?

Push to test,

Turn to open the iris or close to dim....

Did you rotate them closed?

If you did, don't respond to this question...

[Hank]

Those two little lights rotate? Who'd'a thunk?

[gsxrpilot]

Mine are quite loose and the slowly close due to the vibration over a long flight.  But then I fly a C so I don't really ever reference them.

[BKlott]

Mine are quite loose and the slowly close due to the vibration over a long flight.  But then I fly a C so I don't really ever reference them.

Flew a 1968 C Model while working on my Commercial ticket years ago. Had the good old Johnson Bar for the gear. On one approach I thought I had the gear down and locked but the green light that wasn't illuminated said otherwise. Jiggled the lever a bit and the light came on. The Johnson Bar was not quite seated properly but that was not clearly evident until I checked the light that you don't reference.

[N201MKTurbo]

When I had my F, I would be bored flying along sometimes. I would stick my finger in that hole and make the gear lights flash on and off. I felt kind of dirty, but that's how I knew the plane was a girl...

[Andy95W]

When I had my F, I would be bored flying along sometimes. I would stick my finger in that hole and make the gear lights flash on and off. I felt kind of dirty, but that's how I knew the plane was a girl...

Glad to hear I'm not the only one to do that. Might be weird, but at least I'm not alone.

[Rhumbline]

When I had my F, I would be bored flying along sometimes. I would stick my finger in that hole and make the gear lights flash on and off. I felt kind of dirty, but that's how I knew the plane was a girl...

 

Until recently, my gear warning horn switch was grossly maladjusted and would sound at around 18" of MP.  I'd grown so tired of fingering that hole when slowing that my wife, to avoid the annoying squawking that she herself did not produce, would, of her own volition, finger that hole herself. 

 

It's as close as I'll ever get but you may now conjure all the thoughts and comments you wish regarding a me'nage a' tois!   

 

[funvee]

Shawn,

If we give you the answer, how do we know you won't dissapear again..?

Your going to have to give something back.

Sorry, I don't have an answer to your question, but...

These are the two lights, green and yellow...?

Push to test,

Turn to open the iris or close to dim....

Did you rotate them closed?

If you did, don't respond to this question...

Best regards,

-a-

LOL.. No, I didn't rotate them to close the iris  They are the red and the green ones.  

[N201MKTurbo]

I guess we aren't going to talk about how we firmly grabbed that Johnson bar and jacked it up and down.....

[Jerry 5TJ]

Here's the schematic for that area from a 65C.  Voltage is routed to the two lights from one CB to the gear switch and thence to the two lights, which have individual grounds.  

See if your airspeed / gear warning works -- if that is bad, too, then suspect the CB or the wiring that carries +12V from the CB to the gear warning switch (the switch all those guys are fingering in the hole).   You can test it on the ground but you should put the plane up on jacks first to avoid other problems induced by moving the J bar. 

The schematic shows a separate CB for these indicators but in a half-century of murky modification history any configuration is possible: Trust but Verify. 

 

 

Electrical System Schematic Gear Sw Highlight.pdf

[funvee]

Here's the schematic for that area from a 65C.  Voltage is routed to the two lights from one CB to the gear switch and thence to the two lights, which have individual grounds.  

See if your airspeed / gear warning works -- if that is bad, too, then suspect the CB or the wiring that carries +12V from the CB to the gear warning switch (the switch all those guys are fingering in the hole).   

Awesome, this is exactly what I was looking for! Thanks Jerry!

I'll post what I find after I take a look at it today.

Shawn

[gsxrpilot]

Flew a 1968 C Model while working on my Commercial ticket years ago. Had the good old Johnson Bar for the gear. On one approach I thought I had the gear down and locked but the green light that wasn't illuminated said otherwise. Jiggled the lever a bit and the light came on. The Johnson Bar was not quite seated properly but that was not clearly evident until I checked the light that you don't reference.

There is nothing about a red or green light that guarantees gear down and locked. It's just an indication of such. In my C model, I can positively verify the J bar is fully seated and locked by feel.  I use my thumbnail to check for a gap over the top of the bar, and then a sharp downward pull on the bar to ensure it's seated and locked.

 

In other airplanes, without the ability to reach down and perform the same physical verification, the lights are your best indication. 

[funvee]

So i'm out here tracing wirers etc to look for anything obviously not connected but it all looks ok.

I checked that the power after the breaker is ok... It is.

Next I tried to check the power at the gear switch because that appears to be the first step for the power in the schematic. Problem is, I can't get a power reading on any of the three posts in it. It is on a crappy place to get a probe on though so it might be just an accessibility issue on that.

My new questions are: if the gear switch was faulty, would that make the ram air warning light fail as well?

And which switch is it in the parts manual? Is it the AN3224-1 or the gear warning switch BZ-7-RWT80?

And we're do you buy them if it is the problem? I can't find that number on a parts search.

Thanks!

[gsxrpilot]

I'd recommend checking the gear switch next time you're in the air. Just sick a finger up in the empty saddle and you'll feel a thin metal strip that is the switch lever. As you push it up into the saddle, you'll feel a click and the green light should come on. When in a stable cruise, it's easy to move the switch up and down to see exactly when it switches between red and green.

[Hank]

In other airplanes, without the ability to reach down and perform the same physical verification, the lights are your best indication.

My C has a mechanical indicator in the floor. Gear down, it shows green with "GEAR DOWN" in white. When I had winter retraction problems leaving one main down a few inches, it showed red-and-white barber pole. Never pay attention to it in cruise, so don't know the indication. This is in addition to the green "Gear Safe" and amber "Gear Unsafe" lights on the panel.

I always check the floor indicator on final . . . It can't lie, it's painted on the rod between the mains.

[Guest]

Until recently, my gear warning horn switch was grossly maladjusted and would sound at around 18" of MP.  I'd grown so tired of fingering that hole when slowing that my wife, to avoid the annoying squawking that she herself did not produce, would, of her own volition, finger that hole herself. 

 

It's as close as I'll ever get but you may now conjure all the thoughts and comments you wish regarding a me'nage a' tois!

Isn't this a family forum?

Clarence

[mooniac15u]

So i'm out here tracing wirers etc to look for anything obviously not connected but it all looks ok.

I checked that the power after the breaker is ok... It is.

Next I tried to check the power at the gear switch because that appears to be the first step for the power in the schematic. Problem is, I can't get a power reading on any of the three posts in it. It is on a crappy place to get a probe on though so it might be just an accessibility issue on that.

My new questions are: if the gear switch was faulty, would that make the ram air warning light fail as well?

And which switch is it in the parts manual? Is it the AN3224-1 or the gear warning switch BZ-7-RWT80?

And we're do you buy them if it is the problem? I can't find that number on a parts search.

Thanks!

When you press to test it should bypass the gear switch. It seems unlikely that the switch is the problem.

[funvee]

When you press to test it should bypass the gear switch. It seems unlikely that the switch is the problem.

 

That is a very good point!  I hadn't even thought about the way the power in the schematic goes directly to the red and green lights for the push to test to function.  I must have a broken wire between the breaker and the gear switch.  I'll test that line tomorrow and will keep the post updated.

 

Thanks Mooniac15u, you saved me a bunch of extra testing that wouldn't have helped matters.!!

 

Shawn

[funvee]

Ok, this is getting wierd...

I checked the breaker:good

I followed the wire from the breaker to the gear switch as in the schematic: fail

That wire runs all the way up to the back of the Heading indicator where there is a switch with three posts on it.

One post is from the breaker and it has power.

The other two posts look to be running to the panel around the area of the gear lights and maybe the vacuum lights.

Neither of those two post have post.

My guess is that this mystery switch is failing BUT I can't find it in the shop manual or in the parts manual schematics.

Anyone have any idea what it is? I've tried taking pictures of it but it's lable is pointing down and so far I can't get a light to show up more that. The word 'switch' on it.

[funvee]

Disregard that last post... It appears I followed the power line to the vacuum switch. Grrrr

[funvee]

I'm Sooooooo blonde!!! Turns out I followed the wrong breaker output obviously earlier so now that I'm on the correct breaker, the problem was easy to fix..... A bad 5a breaker . What a a fun couple of days

[carusoam]

Nice follow-up, vee.

Best regards,

-a-

[AIREMATT]

Thanks for sharing funvee. At least everyone else learned something at your expense and we all got a good laugh from some of the guys who get their jollies in weird ways with an airplane

[MyNameIsNobody]

What a bunch of hypocrites...