Wiring Help - Want Compressor to run only when ignition is on

I have a basic wiring question for you guys now that I’m honking again :smiley:

I’ve had my kit for about 3-4 years. I have a momentary switch button in the cab. Works great! Only issue I have is the compressor is wired directly to the battery so it runs even when the ignition is off. Part of my last issue is that it ran all night long and burnt up.

I have a 2005 Dodge Ram.

Was looking around the posts on this board but did not find one that seemed to answer this question.

I’m not concerned with running the compressor or horn when the truck is off. Just want to be able to get air and honk when the truck is on.

I have a the service manual for my truck with the wiring schematic but I can’t understand it and was not sure which is the best wire to grab to link the compressor to.

Any suggestions?

you have to wire in a relay… a relay is a switch that when it senses power it will transfer the power to the compressor to turn on… just like a remote lead on a amp for a stereo…

wire it to a ACC fuse / wire… seeying as most acc on vehicles (radio , windows etc) will only work when ignition is on.

Make sense. If I wanted to find a wire to pull the power from under the hood and mount the relay and particular wire to look for that may be a good one to snag power from or a good way to find it?

Here is a good post I found for wiring an air horn on a motorcycle


Here is another good posts about horns and relays and wiring


like said above, strait to a acc fuse in the fuse box and your golden

Yea, its not that hard.
For me, I have a competition stereo system in my truck, so if my head deck is on, my pump has power for the relay. You can tie the trigger line ( 86 on your relay )in on the remote line of an amplifier if u have a setup similar. Otherwise, do what Curtis said.:smiley: