[BusNit]

Thanks for the insight Richard. I will check that by removing my added ground. I used to drive OTR some 30 years ago. I had a buzzer and light for low air. There are three chimes that are all black taped together to form a cluster of 3. I believe one was for the TV antenna being left up, another for the HWH and not sure if the third is for key chime. I looked at my owners manual which suggests there is a ignition chime. Somewhere I was told the previous owner had something serviced which in turn silenced the "annoying" chimes. I tried the diff lock but it did not send any sounds. The switch for it lights up when on. I still like the idea of a low air warning and may just wire in an audible signal to the low air light circuit. Perhaps the same for the stop engine circuit.