jntwps

GOT IT! Thanks everyone for the replies. It was an aftermarket mess under the dash and I had a hard time finding the right places to connect, but eventually found what was mentioned. Works like a charm and is very annoying and loud when it's supposed to be, and silent when it's supposed to stop

This picture below; the bottom switch runs only ground, the top switch (has a white sticker on it) runs power to the low air light. When I use jumpers and connect it to the buzzer, the light stays on constantly, as does the buzzer. This picture below shows only the bottom switch. It is ground. When it's connected to the buzzer and has a power source connected to the buzzer, the buzzer shuts off at 85. When it drops below 85, it buzzes even with the key off/ out of the ignition This is a switch i found online. It's a similar style, but I'm wondering if I need to get it since it looks like it has a positive and negative connector on it, whereas the one on the truck only has a negative connection. I'm sure it's something real simple that I'm overlooking but I can't quite get it working correctly.

Thank you, I think I found the switch. But it’s giving constant power after the pressure drops down. It cuts off at 85, but when the key is out of the ignition and it drops below (even with the low air light off), it starts buzzing

Would either of these be what you’re talking about?

Hi, I'm trying to replace the low air warning buzzer on a 1977 Mack. I haven't worked on it before and the wiring under the dash is suspect. I tested the old buzzer and confirmed it didn't work. Bought a replacement, tested, and it works. The only thing I can do once it's in the truck though is run constant power from the battery to the buzzer. What am I missing? How does this get wired so it shuts off once the air is at an adequate level? This is the style buzzer it had and was purchased to replace it Thanks in advance for helping