In case the horn has failed to operate, it is advisable to look for a fuse and replace it, in-case it is faulty. Check also the voltage and grounding with the horn electrical connection when the horn switch is pressed; if voltage is available then, the horn assembly should be replaced. If voltage or ground is missing look for that particular system in the Chassis Electrical coverage for other troubleshooting procedures and circuits. For a different pitch of the horn, change the horn especially in single horn units. Where vehicles have two horns installed, check second horn by disconnecting one of the horns and then re-check on its operation, install the faulty horn. Also check for dirt or water droppings in the horn and ensure that it is well positioned; where the horn has only one orifice it should be directed downwards to enable free draining and free from dirt accumulation.