Skip to main content

Gear warning horn

The gear warning horn stopped working. Bench tested the horn itself and it worked fine. Continuity checked the throttle microswitch & it is good. Tapped on the microswitches next to gear box and it would sound intermittently, so it seems to be the problem. Not sure which switch is the one. Any ideas where to go from here? If one of these needs replacing, which one, what part #, and where to purchase? Thanks

Model: Bonanza G35
Aircraft Serial Number: D-4484
Posted 6/17/2022 - 1 month ago
|

Replies Sort

John,

There are normally 2 places for the gear horn to operate. One is the throttle switch and the other are the gear safety switch out on the main gear. (Sometimes on one gear sometimes on both). I am not sure how you got the horn to work by tapping the switches on the motor unless you actuated it and it was telling the gear warning that the gear was not safe. I am assuming you are doing these checks on jacks. With plane on jacks and gear in up position pull the throttle to idle. If the horn does not operate you have a problem in the micro switch throttle circuit.

With gear in down position, disconnect both or the single gear safety Switches. If you have a single gear safety switch, after disconnecting the rod, select gear handle to up position and turn Master Switch on. Horn should operate telling you the gear handle is in the up position on the ground and gear should not move. If horn does not sound or gear starts to retract, Safety switch is bad.

On dual safety switch system disconnect both switches. Pull down on one switch to the extended position and turn the master on horn should operate and gear not move. TURN MASTER OFF!!! Release that safety switch and pull down on the other safety and turn MASTER back on. Gear should not move and horn sound. TURN MASTER OFF and reconnect both rods. MAKE SURE YOU TURN MASTER OFF BETWEEN CHECKING LH AND RH SWITCHES!!!!!

These are the only test I know for your gear horn and should isolate your problem.

Posted 6/17/2022 - 1 month ago
|
Quote

John

Follow up to yesterday. Mike sent me this Pete evening.

Bo’s like this G model, the bottom microswitch in the aft stack next top the landing gear actuator is item 7, landing gear warning horn switch, on page 6-11 of the shop manual.

I for some reason had in my head this was in the manual on 35 through 35F, but your G is included in this manual. The other test still apply.

Dale

Posted 6/18/2022 - 1 month ago
|
Quote

If you have the wiring diagrams for the airplane you can tell what switch is what switch by the wire number attached to the switch. I am away from home at the moment so do not have the shop manual/wiring diagrams handy. But the wire numbers are printed on the wires and the ones on my G35 are still very readable.

Regards, Lew Gage

Posted 6/19/2022 - 1 month ago
|
Quote

Thanks Lew & Dale.

I'll be checking on these this week...

Posted 6/19/2022 - 1 month ago
|
Quote

Lew, Checked the wiring diagram as you suggested. Saw that there was a 'flasher' on the circuit. Turns out, it was the flasher that was bad!! Simple solution to a problem we took many hours trying to chase down!!

Posted 6/21/2022 - 1 month ago
|
Quote

That is why we should follow the diagram and eliminate the components one by one.

Bob Ripley
ABS Technical Advisor

Posted 6/21/2022 - 1 month ago
|
Quote

Gear warning horn