wiring compressor

Ive had a trainhorn kit from hornblasters for a few years now with no problems.
My power wire for my conpressor has been wedged into my fusebox undermy ignition fuse. turns out that was a bad idea
How else can i wire up the power wire?

You should be using a relay.
Even Viair’s ‘Ultra-Light Duty’ diagram shows a relay.

Let us know if you have any questions.

I dont know anything about a relay

A relay is basically a switch. It lets you use a low power source to switch a high current circuit.

In our case, we use a low power “trigger” wire from the fuse box to switch the relay. That way, we’re not overworking the fusebox & stock wiring. Then the higher main power wire can be ran straight to the battery with a fuse.

Look at the Viair diagram in the link I posted. The relay pins have standard numbers on them. Pick up a relay from any auto parts store and run the wires like the diagram.

What compressor do you have? And what pressure switch?

Another option is to buy a pressure switch with the relay built in from Hornblasters.

Always use a relay!! Wire it Like ear2ear’s link shows. Also make sure you fuse it correctly. I think it’s on Viair’s site what the amp draw is of the compressors.

im really not sure which compressor or relay I have. all I know is that on hornblaster.com website it the the BETTER kit.

also I don’t understand how to wire up the relay. how does the the compressor not run all the time? where does the relay go? do I still jam a wire into the ignition fuse?
also the pressure switch is wired up with the compressor so how does that get its own prong?
are there any videos you can recommend?

Basically you don’t wanna jam anything in anywhere.

When using a relay to power an accessory (in this case your compressor) there are 2 separate circuits you are creating. Below I will try to explain as simple as I can get without pics.

Circuit 1- compressor’s wiring in order from battery to compressor

  • Connect proper Guage wire using a wiring terminal to the hot (+) side of the battery

  • 3-4 inches away from the battery put in an in-line fuse ( here is where you need to know how many amps your compressor draws)

  • next comes the relay, connect the wire coming from your inline fuse to pin 30 of the relay.

  • connect a wire to pin 87 of the relay

  • connect the wire from pin 87 to the compressors positive wire.

  • connect the compressors ground wire to the frame or you could run the ground the whole way back to the negative (-) side of the battery.

At this point your compressor should be wired up but NOT running

Now the activation switch/wire

Get a Fuse Tap (pictured below) instead of just jamming a wire into your fuse block.

  • Install fuse tap into desired fuse slot. I would suggest your cigar plug fuse because they are normally wired to come on with your key on

  • run a wire to your toggle switch to control your compressor on/off function.

  • from your toggle switch run a wire to your pressure switch. The 2 wire/prong pressure switches normally it doesn’t matter which wire/prong you connect to.

  • run a wire from the unused prong/wire on your pressure switch to pin 86 on the relay.

  • ground pin 85 of your relay to the same point where you grounded your compressor.

At this point you should be able to turn your ignition on, flip your toggle switch and your compressor should work

Here’s how the relay works

Fuse tap- any napa or autozone should have them

Here’s amp draws of compressors, on a side note I think this was made from members here on this forum, right? I’ve seen it before but found it on google.

Good luck!!!

sounds good I get it now, the only problem is that there is no switch for the compressor. the pressure switch tells it when to turn on and off
hornblasters.com says to run the compressor straight to the battery with an inline fuse. then tap into an ignition wire with the pressure switch wire and that will solve the problem. what do you guys think about this idea?

Yeah that’s ok. Just keep in mind that without that extra switch you will not have the ability to turn off the compressor manually (whilst your ignition is on) in case your pressure switch or a hose connection ever fails.