Taxi/Ldg light switch

[Ratso]

1953 C170B Taxi/Landing lights inop. Switch is being supplied with 12V via fuse, but when the switch is pulled to first or second position no power is applied to the terminals supplying voltage to the light bulbs. The switch looks new (case is shiny and the terminal screws are bright brass colored.

I figure I have three options:

A) purchase new switch. Which leads to follow-on questions of; part # and where
B) verify switch wired correctly
C) disassemble switch and lubricate internals

Any advice on which is the best path to take?

Thanks, Ratso

[minton]

Verify voltage available at switch. If OK verify voltage down stream of switch in both positions. If OK ohm out the wires @ the wing root and at the lights. If OK verify the grounding. If OK you are in big trouble.

Good luck!

[GAHorn]

These switches are available from Cessna distributors. PN 0713035 about $30 each. Suggest Hill in Atlanta (http://www.cessnaparts.com)
Minton is offering good troubleshooting tips.
I'm not quite certan I understand your language... "supplied via fuse"...does that mean you actually can measure 12v AT the switch input terminal...but when the sw is activated the output terminals are still dead? (if that is indeed the case...then nothing is lost by opening the switch, cleaning the interior contacts, lubing with light grease and reassembling the switch. I've done this on old switches and they worked out just fine. The metal box is held together with bent-tabs, and the phenolic plate with the terminals has the contacts on the reverse side. I've seen them get dry and corroded, and they can be cleaned up and greased.)

[blueldr]

George,
Is opening up that switch, cleaning the contacts, lubricating, and closing the switch up again, pilot/owner approved maintenance?

Or is that one of those "It depends on whose ox is getting gored" sort of things?

[GAHorn]

Lubrication is preventive mx. (I didn't Ox anybody, Why do you Ox? You disapprove?)

[minton]

Lubrication is authorized. It's the "Open and Closed" that will cost you.

[GAHorn]

OK, then... how about Preventive Maintenance, Pt 43, Appdx A (c) (16):
(16) Trouble shooting and repairing broken circuits in landing light wiring circuits.

[minton]

Broken circuits? Thats not taking switches apart. Remember your limitations. If you insist on working over your plane, take a course and get your A&P then go for it!!

[GAHorn]

At risk of starting a tsunami... whether or not one has an "A&P" or not is NOT the difference between "airworthy" and "unairworthy" repairs/modifications. The actual WORK performed is in accordance with certain criteria.... the certification of that work is another matter completely.
I've seen plenty of good repairs performed by uncertified personnel...and lots of krap performed by so-called "certificate holders". I'm certain you have too.
(These remarks are not intended to encourage circumnavigation of the legal methods of making repairs. They are only my personal observations and opinions. I am far more interested in airworthy repairs than I am in pleasing gov't bureaucrats....and I personally endorse and encourage compliance with FARs. But the quality of the work is obviously far more important than anything else.)

[Ratso]

George's interpetation of my post was correct. 12v is supplied to the switch, but no voltage on outbound terminals when the switch is actuated.

So....I will remove and attempt to clean/lubricate. All under the supervision on an A/P. If unsuccessful, a new switch will be purchased. Thanks for the p/n and place to purchase.

[15A]

A quick little story about my landing light switch.
The damned thing wouldn't shut off sometimes. And it would come on by its self! I didn't want to fool around, so I ordered a new switch. When I removed the old one, there was a stainless steel washer trapped and bouncing around inside of the terminal posts! Should have slowed my wing-overs!

[minton]

George,

Heres your tsunami from me.

I've been sitting back and monitoring many of the posts that spurred me to respond.

A&P or not. There is crap work being done at all levels, from unapproved materials and hardware to the "Farmers repairs" and of course those pesky minor mods that are in fact major modifications that are dreamed up over a beer give the next inspector in line heart burn. My point is that with training, study and supervision, JUST MAYBE the quality of work being accomplished out there COULD IMPROVE. This would go a long way toward curbing some of the "I can do that" resulting in a RE-DO.

If things progress along the lines that I see every day in GA it could result in the need to give some of the owners the option to go "Home Built, Restricted or Experimental" with the restrictions that the designation brings along OR spend the time and money to bring your plane into FAR compliance.

Many of you would like to lend your experise (Help). Please go the extra mile and reference APPROVED DATA, this in my opinion should include reference to "Approved" owner authorized maintenance and of course Factory and Federal publications. Education is simply essential to keep this club moving forward.

NAPA, Home Depot and the like materials don't belong anywhere in certified aircraft.

Darn, even the use of Cherry-Max rivets are now considered to be issues by the Feds. (RE: I/A recert meeting ANC 3/18 2011)

Thats just my humble opinion.

John