gear Warning Horn

[frank.oconnor19]

I think this has been discussed several times, but looking to get some help. Today, I took two flights, on both flights, gear up, throttle open, green light and pump not running. Gear horns sounds, non-stop. I am thinking it is the micro switches in the throttle body. Thoughts?

[n86121]

Easy to adjust (given small screwdriver and nimble fingers).

Easy to replace.
A common 'microswitch' ...if you're not too hung up on FAA sourcing.
Easiest to wire to switch off aircraft on bench, then splice in wire.

[frank.oconnor19]

Where are the switches. In the control quadrant? On the engine? I have the parts manual. But it is not clear, at least not to me.

[n86121]

On top of engine, side of throttle assembly.
Where throttle linkage connects.

An eccentric cam on the throttle shaft opens the switch.
Failure mode is “GAW GAW GAW GAW.”

[frank.oconnor19]

Found both switches. Interesting little setup. In either case the front engine switch is frozen, so regardless of the position of the cam switch remains closed. Rear engine operates normally.

Ordered a new switch. $20.00 so not so bad and frankly not worth bypassing.

Will install over the weekend.

[frank.oconnor19]

I did my tests last week and all is well. 20.00 on replacement wait h and a few wire connectors. Small piece of advice for anyone trying this....make sure you put a clean rag under the assembly. The lock washers and nuts are small and easy to drop. Much better if you have a limited area to search.

[GAdams]

Where do I get those $20 micro switches and what is the part number?

[frank.oconnor19]

so here is the link to the page on airpowerinc.com

http://www.airpowerinc.com/productca...dioGroup=radio

attached are pictures from the parts manual for my plane with the location, top of the engine, and part numbers. hope this helps. BTW the part number in the book, USM5W was replaced by S1856-1

Frank