New train horn issues with squeals/squeaks

I just had a Union Pacific train horn with a 1.5 gal compressor installed in my 2013 silverado. They’re very squeaky/squealy/skreetchy no matter how many times I push the horn. I took it to a custom truck shop who said they have installed train horns before, but it also took them about 7 hours over two days to do the work, when I know most take about 3. Compressor is mounted to driver side by washer fluid and horns are mounted under center front bumper. Is this something that could be from install or a tweak I can do?

These are the specs
3 Bell Train horn with 3/8" HD Valve 1 Each Viair 20003 Compressor tank kit 1.5 gallon 120psi tank/comp dimensions 15" by 14" by 6.5" 1 Each 90-120 psi Pressure Switch 1 Each Horn Button 20 Feet 3/8" Poly Tubing 2 Push connect fittings

Have you checked for water?

Yes, and no water…I heard it doing that when it was being installed, and then once, it was sounding normal, they finished and then now it keeps doing it.

Did you buy those components as a kit?
Is it all new?

Maybe check for kinks in the airline.

Yes they were brand new in the box. I’m not too familiar with all this stuff which is why I went to have it installed at a place who said they have done this before. I know they said they had to use a longer hose from compressor from where they had the horns so it would reach. I emailed the place that I bought it from and just got a reply that they’re sending me new horns Monday. Guess I’ll see if that may be an issue first. This is what i got.

Welcome to the forum. Could your pressure be set too high even with that pressure switch?

Well that’s good they’re helping you out.
Hopefully you’ll be happy once the horns sound right.