Do I need a solenoid for a Hadley...

[John Berger]

If I wire into the factory horn?

 

[mikel]

If you're meaning a 'solenoid' to electrically activate the horn, then no just wire it in place of the stock horn. If you mean a 'solenoid' to open and close the compressed air feed from the tank to the horn, then yes you will need this.



Good luck,

Mike

 

[John Berger]

I'm not sure which one I need or don't need. According to the information on the kits I'm looking at, all say that the compressor automatically shuts off at a certain PSI and kicks on at a certain PSI, but none of the kits list a solenoid as part of the kit.

 

[mikel]

OK, I'm going to kind of describe a 'typical' air system and the pieces that make it up. We'll see if maybe they left something out that's important to what you're trying to do.



Generally your main pieces are:



Air Tank

Air Compressor

Relay - for powering the compressor



Solenoid - this is the electric valve that controls airflow from the

tank to the horns.



Pressure Switch - This controls when the compressor cuts on and off in relation to tank pressure.



I'm not familiar with the specific items included in the Hadley kit, but most that I have seen have been similar. Generally when I install something like this I use the relay to isolate high current components (the compressor in this case) from anything else that may not be up to the current draw. Some kits come with a relay and some don't, so you may have to get one yourself if you want it.



Anyhow, if I install a system like this I'll use a relay and the wiring will be from some ignition-hot circuit to the pressure switch and from the pressure switch to the coil in the relay. The "load" side of the relay is wired to the compressor and the battery direct through a fuse. The reasons that I do it this way are:



The compressor only runs when the key is in the ignition. No dead batteries if the air tank leaks.



The high-current draw of the compressor only goes through the relay, not the pressure switch (This becomes more important as the current draw of the compressor and the distance from the compressor to the pressure switch increase).



The actual "blowing" of the horn happens when 12v (in your case from the existing horn circuit) is applied to the solenoid. Remember that a solenoid (for the purpose of this conversation) is nothing more than an electrically operated valve, so no voltage gives no airflow and 12v gives full airflow making the horns sound.



Whew...



I apologize if I have totally confused the issue, sometimes I'm not too great with typing out my ideas...



Keep in mind that some kits come with a manual valve like some 18-wheelers have for a roof mounted horn. Sometimes the electric solenoid is an extra cost piece.



Hopefully this helps.



Mike

 

[Thomas]

From the Grover site:





#ad






Your install should be similar.

 

[John Berger]

Thanks Mike and Thomas. That helps. I don't have the kit yet, just the Hadley. I'm researching kits now and want to make sure I get everything I need before I do the install.

 

[Bob Wagner]

anyone have a good source for solenoid valves?



looking for an equal to Borg Warner ecs44





Thanks

 

[tgbol]

NAPA sells the Grover electric valve. the Grover #1128 = NAPA 730-1009. You will probably have to order most stores don't stock it.

 

[Big White Beast]

I powered my solenoid from the existing horn circuit...

I had trouble with Napa's solenoid. Seems the draw might have been to high to activate it. When the pressure was maxed it rarely fired. I got a Hadley solenoid from J. C. Whitney. Price was better and it's worked great ever since.



I have mine powered with a $10 compressor from Wal-Mart. Just had to get a pressure switch from J. C. Whitney also. That was around $20. Been close to a year now and no problems. The 1/4" hose is just air brake line available at Napa by the foot. The fittings are standard plumbing compression fittings. If you have the horn already the rest will run you around $100 to get things going. I know the kits are way more than that.



Let me know if you have any questions.



Garrett

 

[JR2]

I used a solenoid for air brakes from a big rig. They can be had at just about any big truck shop. I paid $45 for mine, but I wanted it that day, could have found a better deal.



JR2

 

[RBrunson]

Solenoid

Any of the forklifts out there that run on LPG use a 12v solenoid that will work. Just another source... ...