PCM wiring diagram.
 

I have a 2002 Ranger XLT with the central security system option. My understanding is that with this system, the horn is controlled by the PCM rather than the traditional relay style system. When I push the horn button, I can hear a relay clicking inside the dash to the left or the radio console but the horn (known good) doesn't work.

I have looked looked at dozens of pca wiring diagrams on the internet but can't find one that shows the horn circuit.

Anyone have a diagram for the PCA that shows the horn control circuit?

No, the PCM(engine computer) or PCA? doesn't have any connection to horn.

Keyless entry/alarm can "beep" the horn but wouldn't cause it not to work

In 2002 fuse 35(15amp) in cab fuse box is for the horn, full time power not key on only

The horn button in steering wheel, or keyless entry, Grounds the Horn relay to activate it

Horn relay is in Relay Box 1, which is above gas pedal area under dash, black cover over it, has several relays inside

If you hear the relay "click" when horn button is pressed then fuse should be OK, so could be bad contacts in relay, not passing power to the horn, or the wire from relay to horn is broken

Make sure horn is grounded, many over look grounds and focus on 12volt wiring, need both to get a working device

Relays have two sections, load and coil
This is the Load
Battery------fuse35-------------------(30)horn relay(87)---------------------------horn----ground

This is the coil
Battery------fuse35-------------------(85)horn relay(86)----------------------clock spring------horn button-----ground


Coil activates relay when 12v and ground are both pressent

Load sends 12v from pin 30 to pin 87 when relays is activated

Thanks for the info, RonD.

I looked up under the dash and can see one corner of the backside of a black box mounted above and to the right of the gas pedal. However, it is mounted on the backside of a metal bulkhead and I'll be darned if I see a way to get to it and get the cover off. Do I have to pull out the radio console to get to the front side of the box?

No, the front should face toward steering column, so thats not it

Diagram of relays here: https://www.justanswer.com/uploads/a...12817_rel1.gif

RonD, your picture link isn't working