Need Help

I just got a used set of train horns and I am trying to figure out the wiring on them.

I have most of it figured out, but I was curious if I could run the relay wire and splice it into my power wire for my Black Maxx (my programmer wire runs to a fuse so it turns on with the ignition)? That way the compressor would not turn on until I turn the key right? Would that put too much load on that fuse?

Also the pressure switch on my air tank does not have a positive or negative marked on either of the prongs. How do I know which side of the pressure switch to put the positive wire to or does it really matter?

Any help would be appreciated. I searched on here and couldn’t find anything about those specific questions.

Welcome to the forums. What horns did you get and what are you putting them on?

If it’s the little round style pressure switch, it doesn’t matter which prong is which.

The trigger wire for the relay draws very little current so that’s fine. Some/most people put a toggle switch on their dash for a master cut off. You would run the wire from the pos source - to the toggle switch - to the pressure switch - to the relay. But that would be cool if the programmer had a switched output instead.

BTW - we love pics - haha

They are some I got for free from a guy in trade for my stock muffler. They are made by a company called Kleinn.

I am putting them on a 2008 Ram Cummins.

It is the round style pressure switch so I won’t worry about which side I put them on.

Here is a picture of the compressor and wires.

The yellow wire that says 12V battery fused he had spliced (the main wire going to a fuse and then the battery) and there was a green wire that came out of it to the pressure switch. The big black wire has another green wire that goes to the other side of the pressure switch. The yellow wire with red stripe goes to the positive wire from the compressor. I am not sure what he did with the small black relay wire. I tried to contact him, but he never replied. That is the one I thought about running to the wire that turns on my programmer.

Then the red wires that come out of my horns I was thinking of taking to a push button mounted in the dash, then on to the battery. Is that right?

What is the best place to put the grounds for the horns and the compressor?

Welcome to the forums!

I would advise against running from the same power source, especially if it’s a Dodge Ram. You could end up really screwing up your TIPM (Totally Integrated Power Management) system and the cost to replace it runs well over a thousand dollars. It’s a common issue found on the Cummins forums, and appears to happen to both gas and diesel trucks.

Find another circuit for key-on power and run it from there with a fuse, like the accessory power in the center console, or another key-on source.

Nope, it’s not polarity specific if it’s not marked.


Thanks guys. I am going to see what I can do with it tonight. Hopefully it goes well. I have read a little about the TIPM too and it scares me a little bit.

Yeah, don’t mess with it then. It’s too easy to pick a different spot & fuse it.

No problem … glad I could help :slight_smile:


Got them installed tonight. It was a lot easier than I expected. It was too dark to take pictures when I finished. I still need to install my master cut off switch because I didn’t have enough wire to do that tonight, so hopefully I there are no air leaks tonight. I guess I will find out in the morning. It puts out good sound for a two horn kit. My boss when I lived in Oklahoma had a four horn kit and it was not any louder than this one. I can see myself getting into trouble with these things, hopefully I won’t give anyone a heart attack!

Thanks again for your help guys, I appreciate it.