air compressor blowing fuses

[swynx]

No, to the light bar, unless you are running it thru that 20amp fuse.

You would have at least a 95 amp alternator in a '94 4.0l.

what about an idle at 1200?

 

[enjr44]

so i contacted viair, they said i have to have the truck running because, low voltage can create high amp draw.

however, they said that if i ship it to them, they will inspect it free of charge.

but... after thinking, i think iv always used it with the led light bar on so i can see while airing up in the dark. could this be my problem?

I think Viair has told you what you need to know. You need at least 13.5 volts to the pump to keep it from overheating and blowing the fuse. The battery by itself can not supply 13.5 volts (ever!).

Put a volt meter on the battery terminals and check what you are supplying to the pump with the pump running. If it is not at least 13.5 volts the pump is going to blow the fuse eventually because power (what the pump uses) is volts times amps. So lower voltage requires higher amps to get the needed power. Higher amps always equals more heat and as the pump heats up it will require even more amps to run to compensate for the heat load on the motor (more heat = additional amps, additional amps = more heat, etc.). Eventually you will exceed the fuse rating.

And, FYI, fuses are not there to protect the load (in your case the pump), because in electronic theory, the load is already screwed up and drawing to much power. They are there to protect the power supply and up stream wiring from overload.

 

[swynx]

I can't say that I have used the pump since I replaced my alternator. The old alternator would randomly not hold a constant charge and that's probably what was blowing the fuses. Thanks guys