Subimods Hella Harness - Sanity Check

So, I had some scary situations happen when people ignored my rather timid stock horns here in Chicago. I decided it was time to upgrade to something that will properly get people's attention who are about to drive into me or someone else. Queue buying a set of Supertones which popped up on sale here right about the same time.

 

So I got them, at first thinking "Eh, wiring them up is no big deal, I'll grab some wire". Well I realized my soldering iron is in another state, along with my solder, figured rather than going to the store and buying another, I'll buy a premade harness. Subimods has good reviews, so OK, I order one from them.

 

There were some shipping fiascos with them, but they dealt with it quickly. OK, I get the harness, pull it out, hey, looks very well made/professional, come the day to go do the install.

 

I decide to check the wiring of the harness, just because I'm a bit cautious that way. Hm, first glance, this seems very wrong. Someone check out my findings here and tell me if I'm way off.

 

As best I can tell, the way this is set up you have the signal wire from the stock horns going to pin 30 on the Hella relay. Without tearing open the center shrunk vinyl, I can't tell for sure where the other wires go.

 

In this configuration, the Hellas are going to be fed power from pin 30, which is the original horn wiring, and isn't going to be able to handle the power draw. Is this the way the harness is intended to be wired, or did I get one that is mis-wired? I'm guessing the coil is just always energized, since it's just run straight off the battery.

 

The relay I'm working with, are all Hella relays the same? Maybe this one is different? I think the pin configuration of relays is pretty universal, but maybe that's what's going on?

 

 

The Subimods connector (very nice!)

 

Another nit-pick, and this one is maybe just me over-doing things, but this harness is about 6 feet long. The +12v connection off the battery is fused with a 20A fuse, and is 16AWG wire. The ground wire appears to be 18AWG. Typically I would assume this would be too low, and those should both be 14AWG. I'm not really sure on exact power loading on these though, maybe less of an issue since your horn is unlikely to be under constant power?

 

Does anyone else have this harness? Is it wired the same way? Have you had any issues popping the fuse on the stock wiring?

Nobody? Am I completely wrong here?

i have the harness from subimods but honestly i didnt look at it that intensely. Ive had it hooked up now for ~4months, maybe longer, and use my horn almost daily thanks to the idiots around here. No problems with fuses or anything.

Did you ever confirm the relay was flipping before you hooked the horns themselves up? I've been going over it in my head and can't come up with any way for this setup to function properly.

i have the harness from subimods but honestly i didnt look at it that intensely. Ive had it hooked up now for ~4months, maybe longer, and use my horn almost daily thanks to the idiots around here. No problems with fuses or anything.

 

 

same with me

That's actually the bad part about what I see wrong here. If this is wired as I suspect it is, it will seem like everything is working fine. It looks like 85/86 are hooked straight to the +12v and ground, so the coil will just be permanently energized. 30 is hooked to the original horn wiring, and 87 out to the horns, so you're going to just basically eliminate the relay entirely. Your horns will work fine, until you either overheat the wire (you'd have to lay on them a LONG time), or pop the stock fuse (probably also have to lay on them a while).

^ give Subimods a call and talk to the person who made the wiring harness. Express your concerns / thoughts with them.

speaking of the harness... when i installed mine a little while ago, it seemed like a tight fit. maybe i didnt run the harness the way it was intended. any suggestions for running the harness around the engine bay and such?

Talked to a guy at Subimods, he confirmed the harness is wrong. The information he gave me on the wiring of the harness:

 

Black - Stock horn signal

Blue - +12v from battery (20A fused)

Yellow - +12v to horns

White - Ground from battery & horns

 

With this harness + relay:

Pin 30 - Black

Pin 87 - Yellow

Pin 85 - Blue

Pin 86 - White

 

My understanding is that Subaru's horn signal is ground switched, so black should go to pin 86, blue should go to pin 30, and white has me confused, I need to call him back now. White should be +12v.

At a minimum, all of you guys who are using this harness with the Hella relay pictured (not all relays are the same apparently) should be swapping the blue & black blades on the relay connector.

 

If you don't do this, you are not using the relay to feed additional power from the battery! You are powering them with your stock horn wiring!

 

I don't really know a decent way to communicate this to people, but it's a bit dangerous. Everyone should swap these.

85 or 86 gets fed from the stock horn. The other pin grounds.

 

Battery voltage comes into 30 or 87. The other feeds the horn, chain the horns and ground them on the chassis.

 

No part of the relay should go back to the battery.

 

I'd ground 86 on the bolt you attach the relay to.

 

This setup will energize the coil when you push the horn switch, and close the relay. Any other setup will not work correctly.

OK, so the Subaru horn circuit is +12v, not ground as described on NASIOC/etc? That would make it make sense.

 

The harness is still incorrect, but that makes it possible to function. Everything I had found indicated that the Subaru horn circuit was a ground switch, so I was confused by the other side of the coil also going to ground.

The horn grounds through the mounting bracket. The spade feeding it is +12V. You can verify that with a multimeter, though, if you want.

 

If you want to retain your factory horns, then ground pin 85 or 86 (whichever you aren't using) through the factory horn terminal.

I am not really good with wiring but I can tell you that I am using the subimods wiring harness. When the Hellas stopped working a while back (because my relay went bad) my stock horn still worked. When I replaced the relay with another Hella relay they seemed to work fine.

 

Maybe when I get home I will check the blue and black connector. So the black should connect to 86 and the blue 30?

Correct. Black should go to 85 or 86, and the other of those two should go to ground as long as the stock wiring spade is +12v switched. Blue (+12v from battery) should go to pin 30, and Yellow (+12v output to horns) should go to pin 87.

 

Understand that even wired incorrectly your horns will work, it's just the coil will be permanently energized from the battery and your stock wiring will be the only thing feeding the horns through the (permanently closed) relay.

hmm i'll have to check it out sometime this coming weekend.

Also, stop identifying the wires by color. Identify them by physical connections. Relying on wire color is a mistake. Even the FSM occasionally incorrectly lists wire color.

This is the color on the Subimods harness. It's sealed, so there's no other way to identify them. I didn't want to cut the harness open to figure out where they were spliced together, so I called and got that info from them.

 

Think I'm just going to return this, it's already taken more time than the time I was trying to save making my own.

ShadowImg if you make your own harness please make a write up for it so we can better understand the correct way these horns are to be wired so that way the relay is not energized all the time and only energized when the horn is pressed.

 

Thanks in advance ... as i was about to pull the trigger on one of these harnesses but without a better understanding of how to correctly modify Subimods harness i am kind of hesitant.

Should be wired like this:

 

http://www.rallylights.com/hella/HornWiring.aspx

 

I'm guessing if you call the guys at Subimods and ask for one wired correctly, you can get one. You can verify it pretty easily by looking at it.

 

There are also other harnesses out there I Believe.

It should be wired exactly as I described.

Also that, what you described and that diagram are in sync.

subscribed. i will check my harness before I hook it up next week.

This is the color on the Subimods harness. It's sealed, so there's no other way to identify them. I didn't want to cut the harness open to figure out where they were spliced together, so I called and got that info from them.

 

Think I'm just going to return this, it's already taken more time than the time I was trying to save making my own.

 

If they wire the harness incorrectly, why would you trust their colors as well?

 

Grab a multimeter, and test the leads for continuity to ID them.

^ I don't, I returned the harness. Already cost me the time I was hoping to save with it, so I'm just going to wire them myself.