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Arby49 · 05-11-2018, 05:14 PM

Can anyone explain which of these relays controls my horn? I am terrible at reading schematics!

Bob_C · 05-11-2018, 05:15 PM

So are we when there's not one to read...

Arby49 · 05-11-2018, 05:15 PM

Quote:

Originally Posted by Arby49

Can anyone explain which of these relays controls my horn? I am terrible at reading schematics!

Sorry, forgot photo.[emoji11]

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phays · 05-11-2018, 05:27 PM

Why do you suspect the relay? Are you even sure your coach has a relay for the air horn? Mine does not. Why not the solenoid valve that controls the air to the air horn? On my coach the solenoid was the problem along with insect nests in the air horn bells. I cleaned out the insect nests and 'exercised' the solenoid a sufficient number or times to get it working again.

I would try checking the supply voltage to the solenoid when the horn button is pushed to see if it is getting voltage. If so, the solenoid could be stuck in the closed position or insects have built enough of a next in the air norns to prevent them from working. If no voltage then you can suspect a relay, the horn switch or a fuse.

Once you get the air horns working, exercise them every time you drive down the road to keep the solenoid working.

Arby49 · 05-11-2018, 06:02 PM

Quote:

Originally Posted by phays

Why do you suspect the relay? Are you even sure your coach has a relay for the air horn? Mine does not. Why not the solenoid valve that controls the air to the air horn? On my coach the solenoid was the problem along with insect nests in the air horn bells. I cleaned out the insect nests and 'exercised' the solenoid a sufficient number or times to get it working again.

I would try checking the supply voltage to the solenoid when the horn button is pushed to see if it is getting voltage. If so, the solenoid could be stuck in the closed position or insects have built enough of a next in the air norns to prevent them from working. If no voltage then you can suspect a relay, the horn switch or a fuse.

Once you get the air horns working, exercise them every time you drive down the road to keep the solenoid working.

It's not that I suspedct the relay, I am trying to rule out the simple stuff first. While on a trip one day the horn worked, the next it didn't, so didn't really consider the possibility of critters inside the horn itself.

ZackMan · 05-11-2018, 07:36 PM

Quote:

Originally Posted by Arby49

Sorry, forgot photo.[emoji11] Attachment 202326

The relay for the air horn is on the F8 board top-right. It is a five pin relay.

Arby49 · 06-04-2018, 04:15 PM

Just a quick question. Does that relsy unplug, or is it soldered or bolted on?

ZackMan · 06-05-2018, 04:33 AM

Quote:

Originally Posted by Arby49

Just a quick question. Does that relsy unplug, or is it soldered or bolted on?

The relay is soldered to the board; however, you may want to troubleshoot the VIP SM211 Controller as well. You can test the relay but it necessitates removing the board. There is a troubleshooting guide on VIP’s website for your particular controller.

Their technical specialist is very knowledgeable in regard to the controller.

K7JV · 06-05-2018, 06:52 AM

The control system for the horn includes first, the SmartWheel system including the clock-spring in the steering wheel, the conductors to the module in the front run box and the module, itself. That module has an output that energizes the relay that ZackMan pointed out to you. Up to that point you are talking multi-plex communication, and then low-current relay control power. The relay, when energized, sends operating current to the solenoid operated air valve in your front firewall area, which then sends the air to the horns.

In my experience, probably the most trouble prone piece of that puzzle is the SmartWheel system including the module itself, as well as the clock-spring. The latter has gotten quite a bit of bad press in past years, but I really don't know how troublesome it truly is. If it is bad, though, you should be having problems with your wipers, your cruise control, your ICC head and tail light controls, etc., that are also managed from the steering wheel.

After the module, I would agree with Pete that the solenoid would be suspect. The relay on board #8 that ZackMan pointed out isn't doing heavy work. I would not expect failure, there, particularly since it probably isn't called upon more than a couple of hundred times in its lifetime. In the relay world, that's extremely light duty.

The easiest would be to check first at the solenoid, like Pete suggested. If you do, and the horn still is not functioning, you could remove the air line and check to see if the air is being toggled on and off to the horns.

If you do not have +12V when the horn is called for, I'd next check the connections on board #8. According to the drawings that I have, you should have +12V normally standing on pin #1 of connector J2 on board #8. When the horn is activated, that voltage should go to zero, as the SmartWheel grounds that terminal to enable the horn. You should also see +12V appear on pin #2 of connector J2 on board #8 when the horn is activated. That is the power source for the solenoid in your firewall area.

At that point you'll have your problem nailed down as to whether it is likely the clock-spring, the module, the relay, the solenoid or the horns, themselves, and you can do all of that in a couple of minutes with a simple voltmeter or test light.

Come back here and let us know what you find. Or you can PM any of us for additional help if you need better schematic information. Cheers!

RustyTools · 06-05-2018, 07:16 AM

Pardon the intrusion, but what exactly is the “clock spring”? I’ve heard it referenced quite often.

Bob_C · 06-05-2018, 07:36 AM

Google it...

K7JV · 06-05-2018, 07:49 AM

It is a semi-stiff spiral cable that is shaped like the old escape movement type clock spring. It is at the top of the steering column, under the part you see in the middle of your steering wheel. It allows the conductors to be physically connected to the moving wheel as well as to the non-moving part of the column so that the steering wheel can be turned both ways, stop to stop, and still have the wires connected. It gets its name because it is shaped like a spiral clock spring. When it gets damaged, the communications from the buttons on the steering wheel to the module in the front run box may become intermittent or completely interrupted with all sorts of interesting results.

I once was convinced my clock spring had a problem, and rather than tear into the steering wheel assembly, I let a local shop have a go at it. Turned out the problem was with the module in the front run box. Moisture had gotten into it, somehow, and damaged a circuit board.

RustyTools · 06-05-2018, 08:00 AM

Thanks, Jim.

ctundra · 10-10-2018, 07:58 PM

Did all the troubleshooting from the ground, fuses, power and solenoid working fine. Had a friend work the horn from steering wheel and could hear air getting to the horns. Got on the roof and took the back off both horns, hadley's, and found what looked like insulation packed in the back of the trumpet horns. Stuck a coat hanger down the horn tubes back and forth to clean the big stuff and then blasted air through them. Got all kinds of crude and lots of small stones. Put everything back together and now have awesome sounding horns again. This was the first time cleaning them in five years of owning the motorhome.