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PAI · Air System
EM42270
In stock · ships from Knoxville
This is a cab-mounted plastic air horn control valve. It's a hand-operated lever valve that controls the air supply to your truck's air horn—pulling the cord or chain opens the valve and lets air flow from the tank to the horn.
Confirm the part fits before you buy. Applications and interchange numbers are researched and audited per part.
Verified fitment for 4 applications
Add your truck to see whether it's one of them
All confirmed applications for this part number.
Freightliner
International
Mack Trucks
Other applications
Freightliner
International
Mack Trucks
Other applications
Cross-references to OEM and aftermarket numbers suggest broad interchangeability with many Class 8 trucks that use this style of Grover-type plastic air horn valve. Check port sizes—OEM and PAI EM42270 are listed with 1/8" NPT supply and delivery, but some aftermarket replacements (e.g., Fortpro F224901) have a 1/4" supply port. Verify your existing valve's port threads before purchase.
Part data verified against 4 catalog sources
Numbers this part supersedes or interchanges with. Showing 16 of 38.
Different year, make, or config? Get a confirmation against your truck in under a minute.
Replace it when the valve leaks, sticks, or the plastic body cracks, causing weak or silent horn operation.
Part Number: EM42270
VALVE, MAC20QE29317
Unit: ea
Vendor: PAI Industries
Dealer: KP Services Crossville
Compatibility, alternatives, and more
Parts commonly needed alongside air system
