This is good info...I just started working on my horn at Christmas...I started with the horn and a known good battery..horn works-now working my way towards the steering wheel!!

 

I also have a horn that doesn't work and that's the only thing needed to pass my inspection so that I can get my 66 F-100 4 WD registered in Texas. I checked the relay first and, sure enough, one of the contacts is broken from within and dangling (not that there might not be other problems). I pulled it off and check Dennis Carpenter's but they had a couple that were slightly different. Mine was C4AB-13583-A and I found that at Green Sales for $20 plus shipping. Apparently, the F-100 4WD used the same relay as the F-250 and larger vehicles.

And FYI to anyone pulling a relay off...the headlight circuit passes through the relay so, if you pull it off like I did so that I could read the part# then decide to drive somewhere for the day then come back in the evening, understand that you won't have any lights. (Luckily I'm at a friend's house )

 

C4AZ-13853-A .. Horn Relay (Motorcraft HB-79) / Marked: C4AB-13853-A or C4AB-13853-A2 / Obsolete

Applications: 1965/66 F100/250 2WD / 1966 F100 4WD / 1967 F100/750 / 1968/72 F100/350.

1965/67 E100 / 1969/74 E100/300 // 1964 Galaxie/Thunderbird/Falcon/Fairlane / 1965 Mustang w/a generator.

ANTIQUE AUTO SUPPLY in Arlington TX has 1 = 817-275-2381.

JST AUTOMOTIVE in Lebanon TN has 2 = 615-443-3086.

KINSEL L/M in Beaumont TX has 8 = 800-816-2894.

WOLFE FORD in Lidgerwood ND has 9 = 701-538-7337.

PARTS INTERNATIONAL in Farmers Branch TX has 19 = 888-727-0418.

GREEN SALES CO. in Cincinnati OH has 63 = 800-543-4959.

 

Great info Bill. But are you saying the C4AZ is the same as C4AB? Is that what "marked" means? The pic for the C4AZ on Carpenter's website showed the 3 contacts in a line, whereas mine had 3 in a triangle. The mount on mine was the single mount, as was the C4AZ. And the number your provided is correct. I was going off of memory.

 

There are no Ford part numbers marked on any parts after 1956, only casting or ID engineering numbers (when applicable).

C4AB-13853-A or C4AB-13853-A2 are the Ford ID engineering numbers marked on the part itself, these are not Ford part numbers.

This is the Ford part number: C4AZ-13853-A / This is the Motorcraft part number: HB-79
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ ~~~~~~
Besides the C4AZ-13853-A horn relay, there is another: B8C-13853-A (Motorcraft HB-50) that was used on 1957/60's and other 1961/66's.

Applications: 1957/64 F100/1100 / 1965 F100/250 4WD / 1965/66 F350/1100 / 1966 F250 4WD.

Some B8C-13853-A are not marked, some are marked: C3AB-13853-A

 

More good info. I'm sure Ford had a good reason to use 2 different #s for parts #s and engineering #s on parts besides confusing people.
And that B8C part has 2 mount tabs instead of 1 but the contact arrangement is triangular.

 

I ordered the part number C20Z13A821A, they don't use dashes, from Green Sales Company and got the horn brush without the insulator. Just thought I would save someone the wait and frustration if they was hoping to get the insulator with the horn brush.

 

With or without the dashes, or with or without spaces (C2OZ 13A821 A), makes no difference, the part number is the same.

But, if you type the number into Green Sales' website with dashes, or use a ZERO in place of the correct letter O in the prefix, you get: Sorry, we don't stock this item at this time.

Genuine Ford Parts: C2OZ-13A821-A .. Horn Brush & Insulator Kit. If the insulator didn't come with the kit, it wouldn't have been a kit, now would it?!

I don't use Green Sales' website, you wanna know why? Green Sales and a gazillion other obsolete parts vendors, 25% of the FoMoCo Dealers are listed on PartsVoice.com.

So, when you type the C2OZ-13A821-A part number into PV as I just did, ten sources are listed, not just one.

 

Well, I tried to get the insulator. Thanks anyhow.

 

Thanks to Bill (ND) in helping to source the parts I needed, I took my steering column apart this weekend and replaced the shift collar and shift lever in my 63 F-100. While doing this, I became very familiar with the horn brushes. My truck does not have any insulators around the brushes and it works quite well. The inside brush (making contact between the nylon turn signal part and the steering wheel) is surrounded by nylon and does not need an insulator. The outside brush (between the steering wheel and the horn button) is surrounded by the rubber on the steering wheel and also does not need an insulator.

My horn was not working before I took my steering column apart and in doing the troubleshooting, it was very frustrating because I would get continuity between the inside brush and the horn relay but when I put the steering wheel on, I would not get continuity between the outside brush and the relay. After removing and replacing the steering wheel multiple times, I finally cleaned (with sandpaper) the inside copper brush that mates with the ring on the steering wheel. This worked. Just because continuity is measured with the needle probe of the multimeter, does not mean that it will persist with the steering wheel in place. The brush looked bright and shiny before I started but it must have been dirty enough to not make good contact. Just a thought for all those who are troubleshooting their horns.

By the way, I needed the steering wheel puller the first two times I removed my steering wheel but after that, it wasn't necessary (I won't disclose how many times I had to remove it).

Good luck and thanks again Bill. My truck shifts like new.

David

 

Folks,
i bought a rebuild kit and horn ring as my truck had nada. I replaced all. I tested the horns with wheel off by grounding the brush and they work. The horn ring does nothing and to be honest I don't see how contact is even made. Any suggestions? The horn ring sits kind of wonky when placed on the wheel. This is a 66 F350

 

There is no separate horn wire, the only wires in the steering column are part of the T/S switch.

There are two different coil springs. The one used with a horn ring is different than with a horn button.

Where is the horn brush? All I see is its insulator (7 o'clock in lower pic).

Inside the horn ring, below the nylon retainer is supposed to be a rubber horn blowing pad.

 

working on a 1964 F100 2WD, how do I test the if the horn has power to it from the turn signal switch

 

Take a testing wire/scrap wire
with the wheel off touch the wire from the steering shaft(center of nut) to the little part of the signal switch on the right that sticks up.

there should be a little sling loaded brush there so just check for that. If it’s not there then stick the wire down into the hole to touch the contact.

let us know what happens and we can help more from there if you need it!

 

[QUOTE=NumberDummy;17393121]There is no separate horn wire, the only wires in the steering column are part of the T/S switch.

This is incorrect. The "horn wire" runs through the t/s switch but has nothing to do with any of the many functions of that switch.

The wire originates at the horn relay, goes through the t/s switch and ends at the brush in the steering wheel. It is hot at all times and operates the horn relay when grounded to the steering column by operation of the horn button.

The horn relay operates the horn. The horn button operates the relay. If the relay operates the horn, but the horn button doesn't, there is a lack of ground at either the brushes in the upper column or at the rag joint.

Eric.