I wrote earlier saying I thought I fixed my horn, which was BULL! A lot of the time the horn didn't work previously But I thought I'd fixed the crappy looking horn relay that had some 'slag' welded on the points. Wrong! A week later that horn QUIT working again. I traced this out "like I had good sense" & found that it *wasn't* making ANY contact between the relay horm switch control pin - to where the horn button should make that pin be grounded to the chassis. That connection is supposed to apply the - 12V to operate the relay coil. Because my Haynes book didn't EXACTLY show how to pull off the center of the steering wheel where the horn button is located (a connector is in there too) - what I did was a workaround to fix this thing.
I found which wire on the horn relay socket is the one that goes to the horn button contacts. With a meter I soon found there was NO connetion being made between that relay and the horn switch contacts. You can open a couple of plastic doors in the housing for the steering wheel. Then you can turn the wheel far enough (and lock it there) to reach at least one set of contacts that works the horn relay. Whenever I "shorted out" that horn switch contact with a jumper wire to ground, it should have read as zero ohms on the meter connected to that relay terminal under the hood. But I got NO CONNECTION at all = "infinity".
Then I CUT that control wire off the socket, leaving about 2 inches of wire still connected to the socket to solder a new wire to it. (I made sure to take the negative battery cable off the battery before doing that). A new wire was going to be soldered on to the one that went to the horn button, and a NEW switch was to be installed. The new horn wire would be run from the cab through about a half inch hole drilled in the firewall. This hole was not too far from where the throttle cable passes through that firewall. I taped this wire (2 wires, one is a ground wire) real good so its insulation wouldn't get cut by rubbing on the ragged hole edges. I used a small ***momentary*** red pushbutton (single pole, single throw = "SPST" switch from Radio Shack for $2.50) and soldered the 2 wires on to the switch before mounting that switch into the dash. Be sure to use only flexible wires so as not to strain the small terminals on the switch.
The new switch is mounted just below the steering column on the *left* side. When you drill the 1/2 inch hole for the switch, be SURE to check first to see that hole is FAR enough away from the steering column so the switch can FIT behind the plastic dash-panel. Otherwise you'll make the mistake I did, and drill TOO CLOSE to the steering column. Then you'll discover there is some *other* plastic crap right behind the dash panel - - so you *can't* fit your new horn switch in there!
One wire on the switch has to be maybe 6 or 7 feet (measure this to be sure) and the other wire only needs to be about 2-1/2 feet (?) long. Tape both wires together until they exit through the hole in the firewall. I used some heat shrink tubing on the switch terminals after the 2 wires were soldered to the switch, 'cuz I had some. After you've got both wires pushed through the firewall, use a crimp-on terminal on the short wire and screw that terminal to the firewall with a sheet metal screw - outside the cab. The longer wire will be run to the horn relay and get soldered onto the short horn relay wire that was cut off. You can just use a lot of tape on the solder joint at the horn relay. Make sure to wrap it up securely. I used a bunch of 6 or 8 inch nylon wire ties to bind this new wire to a hose and to a wiring bundle and make it neat.
You gotta have the wires soldered on your small R-S switch FIRST. Make sure the place where the 2 wire are soldered to the switch is THIN. You will need to feed those 2 wires through the approx. 1/2 inch hole in the panel. Then you gotta slide the nut and lockwasher OVER those 2 wires and "feel" them onto the threaded part of the rear of that switch - the part behind the panel. After you get the mounting nut and lockwasher (good luck on that) screwed on the back of your switch, you will need to *rotate* the whole switch with the wires on it, to get that switch tightly mounted. Turn the switch while you hold the nut and lock washer *fixed* in the back. To do that you'll need to roll up those wires in a ball so they can spin around while the switch is being rotated on the front panel. I used my fingers, but the housing of the switch is square so you might could gently use a crescent wrench too. Then use tie-wrap nylon ties to hold the wires away from the brake pedal, ect. - and push the wires through the hole you drilled in the firewall.
Looking at MY relay socket pins, there are 2 parallel pins (these are maybe
1/4 inch long blades really) that run long-wise front to back. Then there is a similar relay pin (another blade) that sits to the *rear* of the 2 front to back blades - and it runs cross-wise to the other 2 blades/pins. On MY horn relay the pin going front to back on the INSIDE of the engine compartment was the 12 volts Positive wire. On this socket, the +12 volts is always present. The blade that runs across (cross-wise) to the vehicle is the one that goes to the horn itself. Then the control wire that puts -12 volts (chassis ground) to the relay and makes the relay operate is the front-to-back pin (blade) that's the one closer to the fender. After you pull out your relay, you can check for +12 volts by reading your voltmeter from chassis ground (-) to the relay blade wide pin that is oriented longways front to back and is the one nearer the engine (+12V). After you read that +12 volts you can pull off the battery negative terminal and perform the ohmmeter tests. The actual HORN resistance on my truck was only about 0.1 or 0.2 ohms!