Seneca air horns and air fill

[Robbbyr]

One of the things I was disappointed with on my Seneca is the really wimpy electric horn. My Focus toad has a far better stock horn! So I embarked on a mission to make things better by installing a set of real air horns. Since our Senecas have an onboard air system I decided to tap into it to accomplish the horns. And while I was at it I also decided to add an air accessory air port so I could fill my own tires or for whatever else I might need compressed air for.

To accomplish the air side I installed a 2.5 gallon auxiliary air tank fed from the chassis "wet" tank through a pressure protection valve. That valve is to ensure that the horn and air fill can never completely deplete the main air system. Then I ran an air line out of the new tank to the air horn mounting location on the right frame rail near the hood hinge. There the air line tees into the air fill regulator and to the horns themselves. Out of the regulator I have a female air quick disconnect. The horns are also mounted here behind the bumper for protection.

To operate the horns I still use the regular steering wheel horn button, but the circuit goes through a dash-mounted Electric/Air horns switch. So I can select either horn I want; a gentle electric "beep", or the sound of a locomotive bearing down! The selector switch is genuine Freightliner used on an American LaFrance fire truck, matches the other dash switches perfectly. I used the same switch connector on the back of the switch that Freightliner uses, so the wiring looks like the factory did it.

To view more pictures of the components please see the album here: http://www.jaycoowners.com/forums/me...lbums1069.html

[Shultz01]

Hi Rob. I want to add air horns as well. I made an extra hole and ordered the switch when I was making the hole for the sideview camera OPT switch.

Couple questions:

1) Where did you pick-up the OEM/stock horn wires to route them back to the horn selection switch on the dash? I'm assuming the wiring that goes from the horn button to the horn now will need to go from the horn to the switch. Then the switch is connected to both horns. Right?

2) I haven't looked at the OEM/stock air tank yet. How and where did you tap into it? Did you put a T in the line or add a port to the tank?

Thanks.
Andy

[Robbbyr]

Originally Posted by Shultz01

Hi Rob. I want to add air horns as well. I made an extra hole and ordered the switch when I was making the hole for the sideview camera OPT switch.

Couple questions:

1) Where did you pick-up the OEM/stock horn wires to route them back to the horn selection switch on the dash? I'm assuming the wiring that goes from the horn button to the horn now will need to go from the horn to the switch. Then the switch is connected to both horns. Right?

Absolutely correct. I removed the harness from the stock electric horn and cut the positive lead a few inches from the connection. From the new horn selector switch I ran three (3) 14-gauge leads through the firewall bulkhead grommet assembly back out to horn area following existing wiring harnesses. I used 3 different color wires to keep the leads separate. The horn "+ feed" from the original horn connection (that I cut) feeds into the center terminal of one side of the new switch. The other two wires connect above and below that connection on the switch, one ties back into the horn connection and the other goes to wherever your air horn solenoid will be located. I ran the new wires in black wire loom like Freightliner did, it is indistinguishable from factory wiring.


2) I haven't looked at the OEM/stock air tank yet. How and where did you tap into it? Did you put a T in the line or add a port to the tank?

On the end of the stock air tank there was a fitting and 1/4" air line leading to the engine's clutch fan. (it's air-actuated). I put a air brake brass tee there reinstalling the original fan clutch line in one side of the tee, the other side is where I installed the new pressure protection valve. Then from the pressure protection valve I ran a new nylon air brake-rated line to my auxiliary air tank which I mounted near the coach battery area. Then out of the air tank I ran a line to the new horn/air regulator area. I got my fittings and air line from a local NAPA heavy truck parts store here in town. They had everything I needed fitting-wise.

The pressure protection valve (PPV) protects the truck's stock air system from ever being depleted due to overuse or leakage in the newly installed air system. It will close off if the main air tank gets to about 70-75 psi. I also installed a pressure relief valve in the new tank (165 psi) and a moisture drain valve on the bottom.

Some might say the second air tank and PPV are overkill, but I wanted to make sure things were as safe and reliable as possible.

Thanks.
Andy

I can get pictures underneath if that would help!

[Shultz01]

Thanks Rob! Much appreciated. The horn description says it includes a "valve" which is 12V--assuming that's a solenoid which is visible in the picture you posted of the parts needed. Just wanted to make sure. Thanks again, Andy

[Robbbyr]

The solenoid was part of the horn assembly I sourced, but not all do come with one. Some horns I saw when shopping did not have one in case you were just replacing them on a big rig and already had a hand lanyard or existing solenoid.

[jasum]

That's AWESOME Rob!!

[jasum]

That's AWESOME ROB!!!! Great job.

[Shultz01]

Rob.

If you're willing to take pictures of underneath--that would be great. I haven't gone under yet to see where the stock tank is located and about mounting the auxiliary one near the coach batteries location. So pictures would be a big help.

I split the electric horn wire today and ran it into the cab to the dash and back out to the horn. I ran the wire for the air horn with it and will continue this wire out to where the air horn will be. I thought horn would be in the front near the bumper--but it was up on the firewall above the engine.

Thanks.
Andy

[Shultz01]

Just crawled under this morning. It looks like there is a Tee there already. One side is the fan clutch like you said and the other side is a relief valve. I just need to put a tee on the tee and I'm all set.

[Robbbyr]

Originally Posted by Shultz01

Just crawled under this morning. It looks like there is a Tee there already. One side is the fan clutch like you said and the other side is a relief valve. I just need to put a tee on the tee and I'm all set.

That is what I did, put a smaller tee into the existing larger one.

To mount my new air tank I fabricated two brackets out of 1.5" x 1/8" steel flat stock forming them into a "J". The throat of the "J" was calculated to allow the "J" to rest on the frame rail (did not want to drill and weaken it) and then the bracket extended under, and bolted to, the battery slideout tray fixed mount. The new air tank then hangs upside down and bolts to the two "J" brackets. I had to be careful and offset the brackets and the holes to mount the tank since the spacing of the air tank's holes and the battery tray mounts are slightly different. After installation I undercoated everything, and I had even painted the "J" brackets before installing to help them last.

Here are some pictures with some callouts pointing out the details. Hope they help.

[Robbbyr]

Originally Posted by Shultz01

I thought horn would be in the front near the bumper--but it was up on the firewall above the engine.

Yes, not the easiest place to access and work on things. I brought the new switched wires all to the horn area and then continued the air horn solenoid wire along the firewall and then down to the area I mounted my new horns and air regulator.

[RyRoRyan]

So on yours, you talked about adding in a separate tank and what not to prevent pressure loss on the parking brakes. I am not sure on yours, but on mine, I have both a "P" guage/tank and a "S" guage/tank. I am assuming that "P" means primary and runs the brakes. "S" means secondary and it appears to run the rear air bags since that tank empties out when I level the coach. Does your coach have the rear air bags / second tank? I am under the impression that I should be able to tie an air horn into the secondary tank system without the risk of impacting my brakes....thoughts?

[Robbbyr]

Originally Posted by RyRoRyan

So on yours, you talked about adding in a separate tank and what not to prevent pressure loss on the parking brakes. I am not sure on yours, but on mine, I have both a "P" guage/tank and a "S" guage/tank. I am assuming that "P" means primary and runs the brakes. "S" means secondary and it appears to run the rear air bags since that tank empties out when I level the coach. Does your coach have the rear air bags / second tank? I am under the impression that I should be able to tie an air horn into the secondary tank system without the risk of impacting my brakes....thoughts?

My 2014 has the rear Freightliner "AirLiner" air spring suspension, but since I do not have air brakes I only have one air "system" and no dashboard air gauge(s). My rig has hydraulically-boosted 4-wheel hydraulic disc brakes versus the newer units with air-actuated drum brakes.

On the older units like mine we do have a separate air-actuated driveshaft parking brake. If I lose all air it would come on as a safety measure, hence my addition of the pressure protection valve so I don't exhaust the air supply accidentally.

To your point, I do not know how Freightliner designed the air system, so I can't say whether tapping into the secondary side could compromise the air system. Your service brakes probably are are on the primary side, but your rear spring (parking) brakes might be on the secondary, as well as the rear suspension. I just do not know. If the rear spring brakes are on the secondary side, dropping pressure too low in that side might cause the parking brake to pop on unexpectedly. Bad news if you are rolling!

[Mustang65]

If you think your current horn is not loud enough make sure you get one of these. I am sure you will get their undivided attention. Turn up the volume on your computer before watching

Don

https://www.youtube.com/watch?v=1GCseAN5V2g

[jvteach77]

Robbbyr - What size aire hose are you using? It looks like 1/4 inch, but the air input on my horn needs a bigger hose or a different connector to connect a 1/4 inch line to it. What size fittings did you use on either side of of the pressure protection valve? I ordered the same one you used, but the threaded openings look really big to me.

Originally Posted by Robbbyr

That is what I did, put a smaller tee into the existing larger one.

To mount my new air tank I fabricated two brackets out of 1.5" x 1/8" steel flat stock forming them into a "J". The throat of the "J" was calculated to allow the "J" to rest on the frame rail (did not want to drill and weaken it) and then the bracket extended under, and bolted to, the battery slideout tray fixed mount. The new air tank then hangs upside down and bolts to the two "J" brackets. I had to be careful and offset the brackets and the holes to mount the tank since the spacing of the air tank's holes and the battery tray mounts are slightly different. After installation I undercoated everything, and I had even painted the "J" brackets before installing to help them last.

Here are some pictures with some callouts pointing out the details. Hope they help.

[Robbbyr]

Originally Posted by jvteach77

Robbbyr - What size aire hose are you using? It looks like 1/4 inch, but the air input on my horn needs a bigger hose or a different connector to connect a 1/4 inch line to it. What size fittings did you use on either side of of the pressure protection valve? I ordered the same one you used, but the threaded openings look really big to me.

My hose is all 1/4" nylon air brake hose. My horn's solenoid valve came with the correct 1/4" compression fitting, if your horn connection is larger you may have to adapt the fittings to get things to connect.

My PPV (from Amazon) has 1/4" threaded pipe fittings on its inlet and outlet. The inlet side of the valve it is connected with a short 1/4" pipe nipple directly to a new tee I installed at the tank outlet. Originally there was just a single air line to the engine's fan clutch there as you can see in Shultz01's picture earlier in this thread. In my annotated pictures you can see the added tee and the new PPV hooked to it. Then out of the PPV I installed a 1/4" pipe thread to 1/4" compression fitting to adapt it to the air line going to my additional air storage tank. At the new tank it tees again to go to the horns and the fill station I mounted underhood.

I can tell my PPV works as intended. If I let the MH sit for a while and the air system leaks down, when I first start the engine I have no (or very weak) air horns. After just a minute of the engine running I will hear a "rush" of air into my added tank, that is when the main air system has built up enough pressure to allow the opening of the PPV to fill my new "secondary" air system. After that system fills the horn works as intended.

If you need any other help or more pictures I can get them, my storage area is 5 minutes away and I visit it regularly in the off season! I am happy to help however I can.

[jvteach77]

Originally Posted by Robbbyr

My hose is all 1/4" nylon air brake hose. My horn's solenoid valve came with the correct 1/4" compression fitting, if your horn connection is larger you may have to adapt the fittings to get things to connect.

My PPV (from Amazon) has 1/4" threaded pipe fittings on its inlet and outlet. The inlet side of the valve it is connected with a short 1/4" pipe nipple directly to a new tee I installed at the tank outlet. Originally there was just a single air line to the engine's fan clutch there as you can see in Shultz01's picture earlier in this thread. In my annotated pictures you can see the added tee and the new PPV hooked to it. Then out of the PPV I installed a 1/4" pipe thread to 1/4" compression fitting to adapt it to the air line going to my additional air storage tank. At the new tank it tees again to go to the horns and the fill station I mounted underhood.

I can tell my PPV works as intended. If I let the MH sit for a while and the air system leaks down, when I first start the engine I have no (or very weak) air horns. After just a minute of the engine running I will hear a "rush" of air into my added tank, that is when the main air system has built up enough pressure to allow the opening of the PPV to fill my new "secondary" air system. After that system fills the horn works as intended.

If you need any other help or more pictures I can get them, my storage area is 5 minutes away and I visit it regularly in the off season! I am happy to help however I can.

That is helpful. My air tank has several more ports in the tank for me to tap into instead of having to add onto the fan clutch like you did. I was planning on removing the plug at one of the two positions on the right and running from there to my PPV and then on to my Horn. Where did you buy the fittings you used to connect the brake hose to the PPV and the horn?

[Robbbyr]

Originally Posted by jvteach77

That is helpful. My air tank has several more ports in the tank for me to tap into instead of having to add onto the fan clutch like you did. I was planning on removing the plug at one of the two positions on the right and running from there to my PPV and then on to my Horn. Where did you buy the fittings you used to connect the brake hose to the PPV and the horn?

Those look like good points to tap into in my opinion. I would suggest you adapt to the tank with solid fittings to the PPV (brass bushing and a short nipple) rather than remote-mounting the PPV and connecting it with tubing. I suggest that so there is less chance of line failure causing you to lose air in your chassis' main air system.

I got my fittings and air tubing from a local NAPA store that specializes in heavy trucks. Had a great assortment of air brake-rated fittings. While a big-box home improvement store might have similar fittings, the ones they sell for trucks are DOT-rated. Might not functionally make a difference, but I tend to err on the side of caution. And I thought the cost for my items was very reasonable.

[RyRoRyan]

I would HIGHLY suggest to tap into the secondary tank, not the primary tank. Even though you are using PPV, the secondary tank runs the rear air bags and the front brakes, the primary tank runs the rear brakes but more importantly, the parking brake, which engages if you lose pressure. I don't know from experience, but you can see this happens often if you drive down the freeway and you randomly see tire marks on the pavement and them dragging their way off the road. Most of these occur due to loss of pressure and brake lockup occurring. I expect that under my tree right now is a box which has a triple trumpet kit in it and I will be doing this install sometime next week if everything I asked for comes

[jvteach77]

I don't recall seeing one, but I'll look again. I have 2 pressure gauges in my instrument panel and sometimes I hear the compressor noise from further back in the coach, instead from near the cab area, so I assume I have a secondary tank and maybe a secondary compressor.