Help Center · Troubleshooting
Diagnose a compressor that will not start or will not shut off — usually wiring, a blown fuse, or a failed pressure switch.
The pressure switch turns the compressor on when tank pressure is low and off when the tank reaches its set pressure. When the switch fails, the compressor either will not start or will not shut off.
If the compressor will not turn on, start with wiring. You may have a blown fuse or a weak / poor ground. On a new install, double-check connections against the kit instructions and wiring diagram — including the in-line fuse.
If wiring looks correct, verify the compressor runs on direct power. Touch the red wire to battery positive and ground the black wire to battery negative or bare frame metal.
The compressor should start immediately. If it does not, the compressor has likely failed and needs repair or replacement.
A compressor that will not shut off is more serious than one that will not start. If pressure climbs high enough to open the safety blowoff, disconnect power immediately.
Remove the fuse from the fuse holder to stop the compressor. Left running, it can blow fuses or permanently damage the unit by pulling more current than it was designed for.
A stuck-on compressor is usually a failed pressure switch. Replacement is straightforward and inexpensive if you are outside the warranty window. Common HornBlasters options:
Each component carries a 1-year warranty through the respective manufacturer. Viair, for example, offers a 1-year manufacturer's defect warranty on their compressors.
If your Viair compressor was purchased less than a year ago, HornBlasters can start the warranty process. Proof of purchase is required. Email Sales@hornblasters.com for details or to open a claim.
Why a compressor may be blowing fuses — worn check valves, exposed wires, poor connections, or faulty carbon brushes.
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