[B2C2]

The problem is that the circuit that looks at the microswitch has a pretty high resistance threshold, like 400 ohms or so to detect closure of the microswitch. Moisture on the switch body between the two contacts can cause the circuit to leak to ground and think the switch is closed. It doesn't help that the screws holding the switch to the throttle body are grounded and quite close to the terminals. Closed is the same as idle, so when you raise the gear with a leaky switch the horn goes off since it thinks you are at idle with gear up. You can test for this on the ground by advancing the throttles with the engines off and seeing if the horn test that you get by pressing the gear up indicator light stops buzzing once you advance the throttles. If it doesn't you have a leaky path in the circuit. I have this happen periodically. Usually flying for a bit dries out the switch and fixes the problem, but the RTV is a good idea. Ill try that.