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Landing Light Switch on 1979 M20J


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My landing light switch seems to be broken.  It will turn on momentarily then turn off (and sometimes flash like a strobe).  I believe I must have bad switch.   I THINK the switch I need is on Lasar's site at the link below as part 930023-235A, but it's sold out (and has an enormous price even if it were available).

What's everyone doing when this happens?  It doesn't look like they have any in stock that are the same even if it were a beacon switch instead of a landing light switch.

https://lasar.com/switches/rocker-switch-landing-light-circuit-breaker-930023-235a

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That switch is a breaker switch.   If it won't stay on check the landing light wiring inside the cowl.   It may be that you have a short circuit that can be repaired.   Once in a while the wiring gets up against the exhaust and gets melted and shorts.   When that happens the switch won't stay on.

 

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17 minutes ago, EricJ said:

That switch is a breaker switch.   If it won't stay on check the landing light wiring inside the cowl.   It may be that you have a short circuit that can be repaired.   Once in a while the wiring gets up against the exhaust and gets melted and shorts.   When that happens the switch won't stay on.

 

I'll check that out, but the switch itself doesn't really click into place well when it's switched on either. it'll some times flop back in the middle between off and on

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If your switch cover is in good shape, you can get that breaker switch with a plain white cover for a lot less money. They are usually available. Just carefully snap off your cover and snap it on the new breaker switch.

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Just now, N201MKTurbo said:

If your switch cover is in good shape, you can get that breaker switch with a plain white cover for a lot less money. They are usually available. Just carefully snap off your cover and snap it on the new breaker switch.

Where might I find a generic circuit breaker switch?  I've been searching around for a couple hours but must not have found the correct one.  Does it use some other part number?  Air Power has some new at 318

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3 minutes ago, N201MKTurbo said:

Yes, it is a 20TC2-BA-15

You should get an LED landing light. You will never have a switch problem again.

Well, thing is, I already have whelen led lights.  I bought the plane two months ago though so maybe this problem was there even before the avionics shop put the led lights in

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3 minutes ago, robert38606 said:

Well, thing is, I already have whelen led lights.  I bought the plane two months ago though so maybe this problem was there even before the avionics shop put the led lights in

If it is tripping with an LED, I would follow Eric’s advice and check the wiring. 

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On 3/13/2022 at 6:24 PM, robert38606 said:

My landing light switch seems to be broken.  It will turn on momentarily then turn off (and sometimes flash like a strobe).  I believe I must have bad switch.   I THINK the switch I need is on Lasar's site at the link below as part 930023-235A, but it's sold out (and has an enormous price even if it were available).

What's everyone doing when this happens?  It doesn't look like they have any in stock that are the same even if it were a beacon switch instead of a landing light switch.

https://lasar.com/switches/rocker-switch-landing-light-circuit-breaker-930023-235a


Robert,

You have defined the classic failure of a worn circuit breaker switch…

They are mechanical devices that wear at an accelerated pace… 

Each time the switch gets operated a tiny spark ejects a tiny atom of metal from the surface….

Over the years… the high current ones wear….

 

Swapping a new one in is a bit challenging… it helps if you have good access behind the panel…

A piece of metal called a bus bar connects it to a family of other CBswitches… taking the bus bar off is part of the job…

 

The hint that it wore out…the click is gone.

The click gets in the way of the switch going over center…

When the click is no longer there, the switch goes over center on its own… or goes over center more easily as it warms up…

 

Get new switch… compare the feel of what a new click is like….  :)
 

New LEDs to go with the new switch… will probably allow the new switch to last forever…

New CB switches are available through aircraftspruce… pay attention while ordering…. They usually come with one cap that is printed… the name on the switch ldg lite will have a -part number for it…

A company called Sensata probably makes the switch, and has a nice technical page for it…. Mooneys use a couple of different versions of it… so make sure you get the right one…

Each switch gets one cap… they won’t allow you to get a second one later… for some reason…
 

PP thoughts only, not a mechanic…

Best regards,

-a-

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I have a new switch with Mooney packaging but it looks slightly different than the Laser part. Marking is the same on face.

Text me and I will send you pictures.  631-804-9677

Part No. 930023-215

Edited by rgpilot
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On 3/13/2022 at 5:24 PM, robert38606 said:

My landing light switch seems to be broken.  It will turn on momentarily then turn off (and sometimes flash like a strobe).  I believe I must have bad switch.   I THINK the switch I need is on Lasar's site at the link below as part 930023-235A, but it's sold out (and has an enormous price even if it were available).

What's everyone doing when this happens?

I have had similar problems with a switch or two.  The switch would not stay ON, unless held in place.  If that is what yours are doing, all they need is to fix the pin that serves as a pivot point. 

As they wear, the pins slide out to the side, and the switch has too much play, so that it will not remain latched in the ON position.  The pins are metal, 1mm or so in diameter and 2-3mm long.  (Those measurements are only from memory and VERY approximate.)  If you can find the pin, it can be put back into position, although it may still work its way out.  I bought replacements on Amazon, (https://www.amazon.com/gp/product/B000N64BN8/ref=ppx_yo_dt_b_search_asin_title?ie=UTF8&psc=1).  (Funny, they were about half as much when I ordered them.  Inflation.)  Unfortunately, I do not remember if they fit perfectly as is, or needed some scraping with an razor blade.  Mine have not been a problem since.

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