Dcs whistle problem

How often do you push the whistle button?  Could it be worn to the point that it doesn't respond all the time?

I've wondered what the "life limit" is on the push buttons and thumbwheel on the handheld remote.  Mine's only a year old but I have seen my thumbwheel behave erratically (smph not change when I move the wheel), but if I keep it slow it works every time.

I hardly ever use the bell button but I do use the horn/whistle button quite a bit.  I find myself pushing down hard on it sometimes and have to remind myself to back off a bit.

Perhaps..... Low track signal.......Dirty track  & wheels.........TIU & remote range.....

I'm going with low track signal.  How much track is on this tiu channel and have you followed barry's wiring suggestions....

I can still get speed function and bell etc to work while the whistle is on which I would guess would rule out signal, unless the whistle button has to be held longer to trigger the engine to stop the whistle.  are these buttons seal from dust or can that get in and goof up the contact?