I have an 03 B2300. Originally it was the base model, no power equipment. I swapped out the doors with power windows/locks. Rather than running wires to make them work I swapped out the dash as well. The doors and dash came from an 01 Ranger XLT. For some reason my horn isn’t working. I checked wire continuity from the clockspring connector to the CSM and from the CSM to the horn and both were good. I put power directly to the horn and it works. I checked for power at the clockspring connector under the dash while pressing the horn switch with no luck. So it appears I’m not getting power to my clockspring possibly. My understanding of the clockspring wiring is the 4-wire connector, the yellow/red wire is the horn signal to the CSM to power the horn. I can’t find in any of the wiring diagrams where the power source to the clockspring is. I know the contacts behind the airbag close to send the signal to the horn, but where does that come from? I changed the clockspring thinking it was the problem, but obviously it isn’t. I’m adding factory cruise control as well so I bought a clockspring with cruise control options.

sorry for the long post, but thanks in advance for any assistance!

 

The horn itself gets 12v from a relay, the Horn Button grounds that relay to activate it

2002 Cruise diagram below

It has clock spring wires in lower right

You see the black/white wire, thats the ground for horn, well every thing in that side of steering wheel, lol

The yellow/green wire(yellow /red on yours) goes to the horn relay, it SHOULD show 12volts all the time if fuse 35 in cab fuse box is OK
If you ground that yellow wire horn should sound, assuming it shows 12v

Horn relay is in AUX relay box 1, it is above the gas pedal and mounted kind of beside the radio facing the Parking brake pedal, has a plastic cover over it

The Central Security Module is a "man-in-the-middle" setup so it can also operate(ground) the Horn relay when you lock or unlock the doors with a fob
So there will be a wire out of the CSM to the horn relay
Horn button------------------CSM-----------------------horn relay----------------Horn

Horn is like brake lights and 4-way flashers, always has 12votls so its fuse is easy to blow when work is being done, because it always ON

 

Ron, thanks for the info! The attached diagram offers a little better detail than the 03 wiring diagrams book I have. One thing that I'm unclear of, and please correct me if I'm wrong, a harnes with power equipment would still have the relay? The diagrams I have don't show the aux relay box as part of the harness. However, they do show the relay box for a harness withought power equipment. If this is the case, then your diagram makes total sense. The CSM will only trigger the horn when the key FOB is pressed to lock/unlock the doors.

Also, my wiring diagrams show fuse 35 is only for trucks without power equipment, but maybe that's incorrect as well.

I'll try to shoot wires this weekend for continuity and power. With it being Easter weekend, not sure how much free time I'll have. Anyway, thanks again for the advice and diagram. I'll report back with my findings!

 

I thought your truck came with no power group

Yes, there will be a horn relay regardless of options, its location may be different but for sure there will be a horn relay somewhere

Rangers all had horn relay since 1989 at least, and in 1995 they all got Park light relay(for flashing lights with Fobs lock and unlock)
Earlier years had the Horn Relay in the engine fuse box, so check there

Yes, the CSM could Ground the horn relay, or the horn button could
It can be a pass-thru in the CSM or CSM has just 1 wire spliced to the horn relay ground wire
Don't have a wiring diagrams for CSMs over the years

You can get PDF of owners manuals here: https://www.ranger-forums.com/genera...1-models-3747/

It will have fuse box layouts for Fuses and Relays

 

my truck originally came without the power group. I swapped in the power doors and full dash, though.

I checked the aux relay box and there isn’t a horn relay in it, not even wires for it on the back side.

I checked fuse 35 and there is 12 volts, but there isn’t a wire on the back side of it.

I checked fuse 1.8 in the battery junction box and it has 12 volts.

I even tried jumping 12 volts to the yellow/light green wire on the air bag sliding contact connector with no luck. I thought that would at least get the horn to sound, but nope.

now to figure out my next steps…

 

I don't thnk I would waste more time on tracking wires since you have all the wires you need

Check that the yellow wire from steering wheel shows as a Ground when either button is pushed
Buy a 4 pole 30amp relay with socket
And get an inline 15amp fuse

Relay will go in engine bay where ever you can find the 12v Horn wire
Standard automotive relay looks like this: https://www.lrukforums.com/media/min...jpg.18440/full
Drawing has 5 pins which is fine you only use 4 pins so either is OK

Pin 30 and 87 are for "the load" the horn's 12volt and rated at up to 30amps
85 and 86 are to activate the relay, about 1/2 an amp, so low draw
There is no polarity on 85 and 86, as long as one has 12v and the other is a ground the relay will close and connect 30 and 87 together

So connect the full time 12v inline fuse to pins 30 and 85, both
Then connect horn wire to 87

Use a small wire on 86, its only 1/2 amp, into the cab and splice it to the yellow wire coming from steering wheel, the ground that activates the horn relay
This is what Fords relay setup was like

If you get keyless entry working then you can add CSMs horn ground wire to this setup so horn beeps when Fob is used

Another popular relay used in vehicles are these: https://www.gtsparkplugs.com/images/...lay-wiring.jpg
Same numbering does the same things, just a smaller footprint as fuse/relay boxes got short on real estate

 

Thanks for the advice! I was hoping to keep it all OEM but to be honest I just want it to work and this would be the easiest way at this point. The one point of clarification I need, the yellow wire from the steering wheel, assume you’re talking about the 2 wires connected to the horn switches under the air bag?

 

No, the yellow/green wire(yellow /red on yours) that runs down steering column to the CSM now, cut it and make sure it shows GROUNDED when you press either horn button, and thats the activation/ground for the realy
No need to get into the steering wheel

Ground----(clock spring)------horn button------(clock spring)-----yellow/red----------------------/ /------------------------CSM

 

Gotcha! I’m more of a visual learner so I’m going to sketch it out to make sure I’m tracking. In the meantime I want to reply to something you mentioned earlier…my keyless entry works fine and has since I swapped the power doors and dash into my truck. However, the horn doesn’t honk when I press the key fob buttons.

 

Yes, that would be because there is no horn relay/wiring to be found

As said I don't have a CSM wiring diagram for any year

After cutting the yellow wire you could test if the CSM's end of that yellow wire shows a GROUND when fob button is pressed but NOT all the time, if so then you can splice that back to its other end and also to your wire to the added relay, so 3 wire connection

So horn button or CSM can ground the relay to activate horm

 

Here’s how I picture I need to wire it up

 

Here are the wiring diagrams I’m using:

Horn/Cigar Lighter with Power Equipment

CSM 274A

CMS 274B

 

Nice work finding those diagrams

So the Horn Relay is INSIDE the CSM

So on Connector C274a, wire on pin 13(Dark Blue) goes to the Horn directly, powered by engine bay fuse 8

So you don't need to add a relay or cut the yellow wire
Once the Dark Blue wire is connected to the Horn it should work, assuming relay inside the CSM is OK and the fuse

Since your Ranger didn't have power group the current horns wire won't run to CSM wiring, I am thinking, so you will need to run a wire from CSM dark blue wire to horns dark blue wire


Yes, your drawing for adding a relay was spot on, just "12v Constant" should be thru a 15amp fuse

 

See, that’s the thing. I previously checked for continuity on the dark blue wire between the CSM and the horn and it was good. I also checked the engine bay fuse and it’s good. I guess I need to try connecting 12V to the blue wire at the CSM to see if I can get the horn to work. If that works then maybe the CSM relay is bad.

as for the diagrams, I bought the FoMoCo wiring diagram book on EBay before swapping the doors and dash.

 

Yes, I would test if 12v at blue wire honks the horn

Also try grounding the yellow wire, CSM connected, to see if horn honks
You should HEAR a relay "click" inside the CSM when yellow wire is grounded

And worst case you can always add a relay, as discussed

You could even add a 2nd relay with diode to activate horn relay when CSM flashes Park Lights using fob
That would need to be in that cab near CSM, but doable

Park lights all use a brown wire for 12v
CSM has a brown wire to flash the Park Lights
But its connected to all the Park lights so when main light switch is used to turn on the Park Lights the CSM brown wire will also 12v, and so would any relay connected to the brown wire, so horn would HONK, while Park Lights were on, lol

A Diode is a one way street for voltage, in this case it allows the 12v to flow one way but not backwards
"--->|---"
The 12v can flow >>>>> the way the arrow points
The 12v would be blocked by |||| straight line side

12v------>|--------------12v
12v------|<--------------0v

You would put a second relay on the brown wire at CSM
This relay is activated by 12v, so 85 is brown wire from CSM, 86 is full time ground, but also connected to 30 so its a full time ground
87 is connected to the yellow wire so it is grounded when this relay activates

Diode goes between 85 and the brown wire that goes out to Park lights, so this wire was cut, end from CSM goes to 85 directly

The diode is like this, Parks lights--------|<-----------85---------CSM

When main light switch is on the 12v is prevented from going thru the diode so relay doesn't activate
But when CSM flashes the Park lights the diode allows the 12v to go out to park lights, AND it activates the 2nd relay, grounds the yellow wire and horn honks