Switch light behavior

When I turn on the MASTER switch, the AVIONICS switch light is lighted regardless of whether the AVIONICS switch is on or off. With the NAV/NAV STROBE switch, both lights light regardless of whether the switch is in the NAV or NAV STROBE position. All other switch lights work as expected, the dimmer works correctly on all lights and the Switch & Fuse module seems to be functionally working correctly.

Could this possibly be the designed behavior? I'm looking at the schematics I downloaded and, I'm not sure I'm interpreting them correctly but, it looks like the AVIONICS switch light gets its power through pin 1 which looks like gets power whenever the EFIS is powered, that is, whenever the MASTER is on. Looking at the schematics for the NAV/NAV STROBE switch, it looks like pins 1 & 2 are tied together which means that both will light whenever one does.

Two separate Switch & Fuse modules have exhibited the exact same behavior.

Me again

My avionics switch light comes on when Skyview boots up regardless of position. Everything else works normally, nav/strobes, landing lite. Sounds like this is normal operation. I rechecked all connections to be sure it wasn't something I did to cause it.

Thanks, Doug. Sounds like your Avionics switch works like mine. My nav light switch is a three position switch: center off, up = NAV STROBE, down = NAV. Both lights are off in the center position, both lights are lit in either of the other two positions. Is that how yours works?

All other switches work as I'd expect: function active = light on, not active = light off. Really weird that these two would be different.

When I turn on the MASTER switch, the AVIONICS switch light is lighted regardless of whether the AVIONICS switch is on or off.

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The light is always on because the avionics switch is being back-fed as explained in THIS POST. Van's is aware of this matter. A possible solution (pending Van's approval) is to remove the wire and pin from D-Sub location 2 of the AV-50001 and move it to location 4 of the AV-50001.

Mich48041 said:

The light is always on because the avionics switch is being back-fed as explained in THIS POST. Van's is aware of this matter. A possible solution (pending Van's approval) is to remove wire P521-18-30-WHT from pin 2 of the AV-50001 and splice it to wire P527-18-30-WHT very close to pin 3 of the AV-50001.

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I do remember that post now that you mention it, I'd forgotten all about it.

Now all I have left is my NAV switch light problem. Still don't know if that's normal. Seems like it might be based on what I think I see in the schematic.

I've been corresponding with Van's support about all this. They didn't think my switch light behavior was normal and even sent me a replacement AV-50001 to try to fix the problem - it didn't.

Now all I have left is my NAV switch light problem. Still don't know if that's normal. Seems like it might be based on what I think I see in the schematic.

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The Nav/Strobe switch lights work as designed. If you want the strobe light to come on only in the strobe position, then wiring changes will have to be made inside of the AV-50001.

Mich48041 said:

The Nav/Strobe switch lights work as designed. If you want the strobe light to come on only in the strobe position, then wiring changes will have to be made inside of the AV-50001.

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OK, that's what it looked like to me as well. Seems odd that it would be designed so both switch lights would illuminate in either position rather than illuminate only the one whose function is selected but it is what it is. Thanks for the response.

avionics switch always lighted

tomkk forwarded an email to me from Van's engineering. It says there is a design glitch on single EFIS panels due to a wiring decision made when accommodating dual EFIS displays. I did the corrective action today and it seems to work. Master switch goes green when on and avionics switch goes green only when on, which seems like the way it should be.

The fix is relatively easy since my avionics bay is currently open. Move one wire from pin 3 to pin 10 on the connector on the back of the switch panel.

I recommend this wiring change whether you are concerned with the light behavior or not. The reason is that the wire that powers SV-D1000 pin 20 could get warm to the touch under certain conditions (Master SW on, Avionics SW off). Moving the wire on the back of AV-50001 from 3 to 10 will eliminate that possibility.
The way to remove a pin is to position the tool around the wire and push the
tool all of the way into the hole before gently pulling on the wire. If the
pin does not come out easily, then rotate the tool 30 degrees and try again.
Keep repeating until the wire comes out easily without pulling hard. Do not
pull the wire until the tool is bottomed out in the hole.

Mich48041 said:

I recommend this wiring change whether you are concerned with the light behavior or not. The reason is that the wire that powers SV-D1000 pin 20 could get warm to the touch under certain conditions (Master SW on, Avionics SW off).

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Not very likely.
The current requirements for the single wire (even if a backup battery is being charged) are well within the spec for the wire gauge used.

Making the change will resolve an unintended functionality of the switch indicator LEDs though.

No change in the operation of the Avionics indicator lamp

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Is there any chance that you could have moved wire 2 by mistake?

I am still puzzled by the brightness of the green light on both the master switch and the avionics switch. Master goes bright green when turned on but stays bright for only a second or two. After that both switches replicate the brightness of the Skyview display screen, including fade to black when the SV is turned off. I can live with that, but it doesn't seem like something the designer would do intentionally. Is this OK?

Special Delivery said:

Seemed like an easy and functional fix, so I gave it a try.... No change in the operation of the Avionics indicator lamp; Avionics switch in the off position, indicator lamp comes on w/Master. <System is what I believe to be the latest hardware / Skyview Touch w/dimmer> Just another day at the office...

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Ernie,
I think you must have made a mistake because Tom (originally started this thread) made the prescribed change and it corrected the function of his switch LED's.

Charlie12 said:

I am still puzzled by the brightness of the green light on both the master switch and the avionics switch. Master goes bright green when turned on but stays bright for only a second or two. After that both switches replicate the brightness of the Skyview display screen, including fade to black when the SV is turned off. I can live with that, but it doesn't seem like something the designer would do intentionally. Is this OK?

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All panel lights (LED's in the switches) and the cockpit flood light, by design are controlled by the dimmer with the Skyview screen. Until the screen is fully boot, the light intensity is uncertain. What it is fully booted, the panel lights are synchronized to the screen intensity.

Switch indicator lamps work as expected!

rvbuilder2002 said:

Ernie,
I think you must have made a mistake because Tom (originally started this thread) made the prescribed change and it corrected the function of his switch LED's.

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My apologies to all and I will delete my earlier post... Peanut Butter & Jelly, Salt & Pepper, Bread & Butter, and Ernie & Mistakes. Yep, all these go together.

Sorry for the delayed response but I wanted to report a complete story. I assigned the task of moving pin 3 to pin 10 to one of our very capable students. After testing and finding that the indicator light problem didn't change, I reported it here and the responses indicated that the job may not have been completed correctly. So... here's the report;

I asked the student to physically show me his work. It appears he made an incorrect assumption based visual inspection of the occupied pins and he did not confirm actual pin numbers. Because there was a pin in what he thought was pin 3 (11) and there was no pin in what he thought was pin 10 (4), he actually moved pin 11 to pin 4. An easy mistake I suppose because the wiring schematic indicates no connections in position 3 and 4 and it appears this is how our switch harness was shipped. So... we rang out the harness to the current schematic and PROBLEM SOLVED.

Thanks to all... Sugar & Cream