Diagnose a 127H / 228H air source when the compressor will not run or will not shut off. These units are pre-wired to the pressure switch, which can make testing a little confusing at first.
What you need: 12V battery access, Windex or soapy water for leak checks, and a solid ground point
Compressor Does Not Run Anymore
If the air compressor on your 127H / 228H system is no longer running to fill the tank, here’s how you can diagnose it. The compressor on these systems is pre-wired to the pressure switch for your convenience.
1
Bench-test power at the compressor red lead
To test the air compressor you will want to route power from the battery positive terminal (or any 12-volt power source) over to the red wire coming directly off the compressor. This red wire is connected to the pressure switch with a bullet connector. These can be pulled apart with enough force to expose two leads.
Route 12 volts to the red wire coming directly off the compressor itself. The compressor should start to run and fill the tank. Ensure the ground point for the compressor is good and solid before doing this test.
Separate the bullet connector and feed 12V to the compressor red lead.
2
Read the result
If the above does not get the compressor to run, please contact us directly for assistance in starting the warranty process.
If the above does allow the compressor to run and fill the tank, your pressure switch (the small piece with two wires) has failed and needs to be replaced.
A direct-power test isolates the compressor from the pressure switch and vehicle wiring.
Compressor Won’t Shut Off
If the compressor on your system won’t stop filling the tank, the compressor may not be building enough pressure to actually shut off.
3
Check the safety blow-off first
Does the compressor pop the safety blow-off valve after ~4–5 minutes?
Yes: Your pressure switch has likely failed.
No: We could have a leak somewhere, or a bad compressor. Let’s troubleshoot further.
4
Check for leaks and a stuck blow-off
Check the drain cock fitting on the tank and make sure it’s not leaking air. If it is, rotate the drain counter-clockwise to close it.
Spray down the system with Windex or soapy water. Do any of the fittings or connections bubble up? If a fitting starts bubbling, this indicates that it is leaking. The leak must be corrected by tightening the fitting, or applying a sealant around the thread of the fitting.
Check and make sure that the blow-off valve is not stuck open.
If none of the above steps make a difference, you may need to warranty the compressor out.
Pull power if pressure climbs unchecked. A stuck-on compressor can damage the unit.
Warranty
5
127H / 228H coverage through HornBlasters
All 127H / 228H air source kits are warrantied through HornBlasters. Give our team a call at (877) 209-8179 to start the process, or email us at sales@hornblasters.com.
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How to relocate the compressor air filter for a cleaner, drier intake.
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