The causes of malfunctions of sound signals can be the following: the switch does not work or sticks, or the sound signal is damaged.
To detect a malfunction, check the reliability of the wire connection, the condition of the switch contacts. Clean contacts if necessary. Replace the defective switch and sound signal with new ones.
If the sound strength decreases or wheezing appears, adjust the signal. Adjust by turning the screw on its body in one direction or another until a loud and clear sound is obtained.
If the adjustment does not eliminate wheezing or if the signal is intermittent, then disassemble the signal and clean the contacts of its interrupter.
When assembling the signal, it is necessary to install the previous gasket between the membrane and the signal housing so as not to disturb the gap between the core and the armature.