Horn question - Power Steering from M39 series

[tcruwithme]

Last year I bought a power steering system from a vendor who said it was pulled out of an M818 tractor - to install into my 1985 M35A2C for power steering. The gear box is on the steering column, so it appears that it was originally from an M39 series of 5-Ton truck. I found a few references to the horn and power steering systems in 2320-211-20-3-1 and 2320-211-20-3-1 as well as in the 24p TMs. In other words, I did read the TMs before posting this question

The steering kit showed up with no horn button assembly of any kind. I have a newer style 18" steering wheel, and I now need to figure out how to get the horn wired up. I know I'll need some sort of horn button kit. Ted from Real Custom Trucks is helping me with that. What I need to figure out is how to get a wire down through the steering column, and where it goes from there - where does it come out of the power steering column?

Here's a couple pics of the top of the steering gear box on the steering column in my M35A2C:



Here's a couple picks of my steering wheel in the cab:



What is the best way to get this horn wired back up? Any guidance you can provide is greatly appreciated.

 

[Hawssie]

Do you have electric horns? If you have air horns like the m939 you can hook up an air valve like most all big rigs. its just a mechanical air valve with a chain that is normally located to the right of your head above the front door. You just pull the chain when you want to blast the horn. Thats how the M1070 works by the way. But if its electric horns (or even air) then the factory button would probably be cleaner and easier. There is a breakdown that you may not have not seen in TM 9-2320-272-23-2 toward the end on page 0334. As far as hooking up the horn button, On the M939 set up there is an electric over air solenoid that allows air pressure to actuate the air horns. This circuit is completed with a momentary switch (which is the horn button) that connects 24v+ to the solenoid, the solenoid opens allowing air to the horns. Ironically almost all automotive horn buttons are ground wired. But this is a Military vehicle with a air solenoid.

 

[ke5eua]

Thats how the M1070 works by the way.

This circuit is completed with a momentary switch (which is the horn button) that connects 24v+ to the solenoid, the solenoid opens allowing air to the horns.

1070 has two horn systems, the manual air horn and a lower volume button horn.

The button does provide negative voltage to the solenoid. Constant + on one side of the solenoid and - from the button. Part of the troubleshooting procedure is to see if the +24 is present at the solenoid.

 

[Hawssie]

Is this on the M939 or the m1070. I thought I saw the solenoid grounded on the M939 wiring diagram. I will have to look again. The extra horn button for the m1070 is like the automatic trans, to make it more "familiar" for the average person, you wont see either one on many big rigs.

 

[porkysplace]

Lets get back on topic he is working on a M35A2C with a early 5 ton ( M39 ) steering box not a M939 or M1070 .

PM
vtdeucedriver
He started a similar thread last april but never updayed it and there were no replies

 

[Hawssie]

Your right I misread it, I thought the switch icon was the solenoid ! I guess its time to get some glasses. So it is wired like a typical horn button, so replace the 24v+ with ground in the above!

 

[ke5eua]

Is this on the M939 or the m1070. I thought I saw the solenoid grounded on the M939 wiring diagram. I will have to look again. The extra horn button for the m1070 is like the automatic trans, to make it more "familiar" for the average person, you wont see either one on many big rigs.

939, for horn polarity.

1070 about the dual horns. I agree about convince factor on that one.

 

[Hawssie]

Well one thing he asked was how to hook up the horn button on a m939 steering column. Since I dont know anything about the older 800's trucks thats all I tried to provide. Someone else can provide the rest.

 

[porkysplace]

Well one thing he asked was how to hook up the horn button on a m939 steering column. Since I dont know anything about the older 800's trucks thats all I tried to provide. Someone else can provide the rest.

Re-read his post he ask about a M39 steering column ( M818 was posted ) not M939.

[ Last year I bought a power steering system from a vendor who said it was pulled out of an M818 tractor - to install into my 1985 M35A2C for power steering. The gear box is on the steering column, so it appears that it was originally from an M39 series of 5-Ton truck. I found a few references to the horn and power steering systems in 2320-211-20-3-1 and 2320-211-20-3-1 as well as in the 24p TMs. In other words, I did read the TMs before posting this question ]

 

[ke5eua]

Well one thing he asked was how to hook up the horn button on a m939 steering column. Since I dont know anything about the older 800's trucks thats all I tried to provide. Someone else can provide the rest.

800 series is the same.

Re-read his post he ask about a M39 steering column ( M818 was posted ) not M939.

The contact box looks like the upgraded version. Given that the column would provide -24VDC. If the solenoid requires +24VDC he will either need to add a relay to actaviate -24V to the solenoid or remove the ground from the solenoid, add a constant +24 and run the column to the other side of the solenoid.

Easy peasy

Edit:

Forgive me, I did go through Lousiana public schools so I'm a little slow, lol

Just noticed it is on a deuce. Bam problem solved, fix the wire, plug it in. You require a ground from the column anyway. Same solenoid that is on the 800, 900 series, same wiring for the horn setup.

 

[tcruwithme]

Thanks for your input everyone. Yes, I am working on a power steering system from an older M39 series 5-Ton truck. The steering wheels is a newer style, and the opening for the horn button measures 3.5" across. I've read other posts where I saw someone say "don't even try to push a wire down the steering column," so I was wondering if there was a trick to it - or if getting a wire up to the horn button by the steering wheel is impossible.

I am also wondering if the small box on the steering column right above the steering gear box has something to do with the horn. This can be seen in my attached photos on the original post.

 

[ke5eua]

Thanks for your input everyone. Yes, I am working on a power steering system from an older M39 series 5-Ton truck. The steering wheels is a newer style, and the opening for the horn button measures 3.5" across. I've read other posts where I saw someone say "don't even try to push a wire down the steering column," so I was wondering if there was a trick to it - or if getting a wire up to the horn button by the steering wheel is impossible.

I am also wondering if the small box on the steering column right above the steering gear box has something to do with the horn. This can be seen in my attached photos on the original post.

Correct, don't try and push it down. The box in the picture is for the horn.

I don't know of a trick to fix it, mine failed and I just pulled the wire out from the bottom.

From what I could gather from looking at it the wire goes to a piece on the bottom of the shaft and there is a little slip ring type device that rides on it to allow contact at all times when the steering wheel turns.

 

[tcruwithme]

Ok. I spent some time trying to figure out this horn project again. Here's what I have in the center of the steering wheel. I am guessing it is not what is supposed to be there. At least, this is not what the TMs say should be there. I got a horn button kit from Ted at Real Custom Trucks not too long ago, but it looks like it wants a different type of horn contact instead of this wire and plug.



Here's the box on the steering column. Can anyone tell me what is supposed to plug into this box? ke5eua said below that I should have a horn solenoid that is the same as in the 800 series trucks. My guess is that this solenoid is missing from my truck, as my truck is an M35A2C with this steering system from the 5-ton.



I really hope I can get the horn set up like it is supposed to be. I know that I can do a pull string or a different type of push button - but that is a last resort.

 

[AMGeneral]

OK,bear with me here,it's been a while since I disassembled one of the older style columns.

It looks as if you had the "later" style horn button kit installed on that box/column at one point(the wire end sticking out of the column gives it away,I have the same type on my M51 dump) It has a rubber "filler" that goes in the center of the steering wheel and a small (1 1/2 inch diameter) button that is held in with a snap ring.

Although a mil spec item,I have not seen any of the dealers carry it(rare?).

There should be 2 wires plugged into your horn solenoid,one will have 24 volts on it at all times,the other will be from the solenoid to the connector protruding from the metal box at the base of the steering column you have.

Being the deuce originally had the wire coming out of the bottom of the steering box,the wire for your horn "should" be in this general area.

Just connect this wire to the connector mentioned above.


Once you make this connection,you should now have 24 volts at the wire protruding from the steering column at the steering wheel.

Then it will just be a matter of finding the correct horn button kit to finish the job.

 

[tcruwithme]

Thanks a ton, AMGeneral!

I do have a male Packard connector hanging loose down by the driver side fender bracket. My guess is that used to plug into the bottom of the Deuce steering column for the horn. I'll run a wire from that up to the box on the steering column as you suggest.

I think the horn solenoid is on the actual air horns, is that correct? My truck is parked 80 miles away, so I can't look at it right now. I do remember seeing two wires running into the horn assembly - into what looks like a solenoid. So that will be easy to check to see that one side has power and the other goes to the box on the steering column we have been talking about.

So, the only mystery part that remains is finding the correct horn button kit. Or, can I cut off that Packard plug and put a different contact connection on the end - so that I can use a different horn button kit?

Thanks again for your help. I'm not a mechanic, not an engineer, not a fabricator - so Steel Soldiers is a life saver for me!

OK,bear with me here,it's been a while since I disassembled one of the older style columns.

It looks as if you had the "later" style horn button kit installed on that box/column at one point(the wire end sticking out of the column gives it away,I have the same type on my M51 dump) It has a rubber "filler" that goes in the center of the steering wheel and a small (1 1/2 inch diameter) button that is held in with a snap ring.

Although a mil spec item,I have not seen any of the dealers carry it(rare?).

There should be 2 wires plugged into your horn solenoid,one will have 24 volts on it at all times,the other will be from the solenoid to the connector protruding from the metal box at the base of the steering column you have.

Being the deuce originally had the wire coming out of the bottom of the steering box,the wire for your horn "should" be in this general area.

Just connect this wire to the connector mentioned above.


Once you make this connection,you should now have 24 volts at the wire protruding from the steering column at the steering wheel.

Then it will just be a matter of finding the correct horn button kit to finish the job.

 

[AMGeneral]

Thanks a ton, AMGeneral!

I do have a male Packard connector hanging loose down by the driver side fender bracket. My guess is that used to plug into the bottom of the Deuce steering column for the horn. I'll run a wire from that up to the box on the steering column as you suggest.

I think the horn solenoid is on the actual air horns, is that correct? My truck is parked 80 miles away, so I can't look at it right now. I do remember seeing two wires running into the horn assembly - into what looks like a solenoid. So that will be easy to check to see that one side has power and the other goes to the box on the steering column we have been talking about.

So, the only mystery part that remains is finding the correct horn button kit. Or, can I cut off that Packard plug and put a different contact connection on the end - so that I can use a different horn button kit?

Thanks again for your help. I'm not a mechanic, not an engineer, not a fabricator - so Steel Soldiers is a life saver for me!

Yes,the horn solenoid is mounted on the air horn itself,being a deuce,probably on the right inner fender.

I think the horn button kit for a 900 series 5 ton will work,if not maybe one of the dealers will have one in stock.

 

[tcruwithme]

Geeze. This horn issue is a never-ending problem. So I thought my solenoid was bad,and I replaced it with a new one from Erik's. Turns out the solenoid was just fine. I have 24 volts at the solenoid, and when I supply it with ground right at the solenoid, the horns just blow air but no horn noise. Great. Other SS members suggest cleaning out the horns or replacing if necessary.

In addition to that, I still have an issue with getting the horn button to supply ground through the steering column. The horn button is the new style, and it's hooked up correctly. I am not sure where the other end of the wire goes once it goes down through the center of the steering column. The box on the steering column on the engine side of the firewall has a spring connector under it that presses directly onto the rotating steering column. That suggests that the spring up under the horn button is not making a ground connection. Oh, well, I'll get this figured out sooner or later.

In the process, I've read the TMs for the M36 series, the 809 series, and the 939 series of 5-ton trucks. I've built my own "5-ton Horn TM" just for the fun of it.

 

[ke5eua]

Pics of the setup so we can point you in the right direction.

You cops take some sand paper to the shaft under the spring to clean it up. Use some high grit. Also take a multimeter to it and verify it is getting a good connection when the button is pressed.