| whiterock91 - 1/8/2025 12:10
It is most likely the expansion valve by the receiver dryer on the front of the cab on the passenger side. If you run the engine fan, it shouldn't make that noise. The AC still works fine, but there is something wrong in that valve that causes a vibration in the valve under high pressure. Replacing that valve should fix it.
ETA,
There is also an expansion valve under the sleeper on the passenger side, if you have a sleeper on your truck.
Thanks, that’s exactly what is making the noise. I stood there with the hood open and touched the expansion valve, and every time the compressor kicked in I could feel a vibration there and just barely hear the horn noise over the noise of the motor idling, the noise is much louder inside the cab. |
Weird random air horn noise on my truck?
